diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..dea22ea
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+sysroot
diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..6a9bda7
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,5 @@
+Please see the LICENSE file in each top-level directory for the terms applicable to that directory and its relative sub-directories.
+
+The relevant directories and licenses are:
+
+basics/      - CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..8ae722f
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,40 @@
+# These variables are specifically meant to be overridable via
+# the make command-line.
+WASM_CC = clang
+WASM_CFLAGS = -O2
+WASM_TARGET_FLAGS = --target=wasm32
+SYSROOT = sysroot
+
+# These variables describe the locations of various files and
+# directories in the source tree.
+BASICS_DIR = basics
+BASICS_INC = basics/include
+BASICS_LIBC_DIR = $(BASICS_DIR)/libc
+BASICS_LIBC_SOURCES = $(BASICS_LIBC_DIR)/string.c
+
+.PHONY: $(SYSROOT)
+$(SYSROOT):
+	$(RM) -r "$(SYSROOT)"
+	mkdir -p "$(SYSROOT)/usr"
+
+	#
+	# Install the include files.
+	#
+	cp -r  "$(BASICS_INC)" "$(SYSROOT)/usr"
+
+	#
+	# Build the C startup files.
+	#
+	$(RM) *.o
+	"$(WASM_CC)" $(WASM_CFLAGS) $(WASM_TARGET_FLAGS) --sysroot="$(SYSROOT)" -c $(BASICS_LIBC_DIR)/crt*.s
+	mkdir -p "$(SYSROOT)/lib"
+	mv *.o "$(SYSROOT)/lib"
+
+	#
+	# Compile and install the libc-subset source files.
+	#
+	$(RM) *.o
+	"$(WASM_CC)" $(WASM_CFLAGS) $(WASM_TARGET_FLAGS) --sysroot="$(SYSROOT)" -c $(BASICS_LIBC_SOURCES)
+	mkdir -p "$(SYSROOT)/lib"
+	ar crs "$(SYSROOT)/lib/libc.a" *.o
+	$(RM) *.o
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..ecd58b5
--- /dev/null
+++ b/README.md
@@ -0,0 +1,48 @@
+# WebAssembly Reference Sysroot
+
+Caution: This is currently quite experimental and not generally usable yet!
+
+## What is this?
+
+This is a "reference sysroot", which is meant to be part of a common C ABI
+that can be shared across C libraries and compilers. While it's intended to
+(eventually) be usable in its own right, we fully expect other
+implementations to be used in practice by many different systems, though
+we do hope that in those cases, this library defines a useful ABI that can
+be followed.
+
+## Usage
+
+Obtain a WebAssembly-supporting C compiler, and then run:
+
+```
+make WASM_CC=/path/to/wasm/supporting/c/compiler
+```
+
+This makes a directory called "sysroot", by default. See the top of the Makefile
+for customization options.
+
+To use the sysroot, use the `--sysroot=` option:
+
+```
+/path/to/wasm/supporting/c/compiler --sysroot=/path/to/the/newly/built/sysroot ...
+```
+
+to run the compiler using the newly built sysroot.
+
+## Why doesn't this contain a full libc implementation?
+
+In the short term, one of the main goals is just to provide a reference
+point for people already maintaining their own libc codebases, to help
+reduce interface incompatibilities between the several different
+environments out there.
+
+In the long term, there may some day be some form of standardized
+syscall/import layer for wasm which would could support a full
+"reference libc", at which point this repository might make sense as
+a place to host such a thing.
+
+In between, if there are specific pieces of libc functionality which
+people would find useful to have here, and which don't depend on any
+syscalls, we could add them, using code from existing third-party
+codebases as appropriate.
diff --git a/basics/LICENSE b/basics/LICENSE
new file mode 100644
index 0000000..0e259d4
--- /dev/null
+++ b/basics/LICENSE
@@ -0,0 +1,121 @@
+Creative Commons Legal Code
+
+CC0 1.0 Universal
+
+    CREATIVE COMMONS CORPORATION IS NOT A LAW FIRM AND DOES NOT PROVIDE
+    LEGAL SERVICES. DISTRIBUTION OF THIS DOCUMENT DOES NOT CREATE AN
+    ATTORNEY-CLIENT RELATIONSHIP. CREATIVE COMMONS PROVIDES THIS
+    INFORMATION ON AN "AS-IS" BASIS. CREATIVE COMMONS MAKES NO WARRANTIES
+    REGARDING THE USE OF THIS DOCUMENT OR THE INFORMATION OR WORKS
+    PROVIDED HEREUNDER, AND DISCLAIMS LIABILITY FOR DAMAGES RESULTING FROM
+    THE USE OF THIS DOCUMENT OR THE INFORMATION OR WORKS PROVIDED
+    HEREUNDER.
+
+Statement of Purpose
+
+The laws of most jurisdictions throughout the world automatically confer
+exclusive Copyright and Related Rights (defined below) upon the creator
+and subsequent owner(s) (each and all, an "owner") of an original work of
+authorship and/or a database (each, a "Work").
+
+Certain owners wish to permanently relinquish those rights to a Work for
+the purpose of contributing to a commons of creative, cultural and
+scientific works ("Commons") that the public can reliably and without fear
+of later claims of infringement build upon, modify, incorporate in other
+works, reuse and redistribute as freely as possible in any form whatsoever
+and for any purposes, including without limitation commercial purposes.
+These owners may contribute to the Commons to promote the ideal of a free
+culture and the further production of creative, cultural and scientific
+works, or to gain reputation or greater distribution for their Work in
+part through the use and efforts of others.
+
+For these and/or other purposes and motivations, and without any
+expectation of additional consideration or compensation, the person
+associating CC0 with a Work (the "Affirmer"), to the extent that he or she
+is an owner of Copyright and Related Rights in the Work, voluntarily
+elects to apply CC0 to the Work and publicly distribute the Work under its
+terms, with knowledge of his or her Copyright and Related Rights in the
+Work and the meaning and intended legal effect of CC0 on those rights.
+
+1. Copyright and Related Rights. A Work made available under CC0 may be
+protected by copyright and related or neighboring rights ("Copyright and
+Related Rights"). Copyright and Related Rights include, but are not
+limited to, the following:
+
+  i. the right to reproduce, adapt, distribute, perform, display,
+     communicate, and translate a Work;
+ ii. moral rights retained by the original author(s) and/or performer(s);
+iii. publicity and privacy rights pertaining to a person's image or
+     likeness depicted in a Work;
+ iv. rights protecting against unfair competition in regards to a Work,
+     subject to the limitations in paragraph 4(a), below;
+  v. rights protecting the extraction, dissemination, use and reuse of data
+     in a Work;
+ vi. database rights (such as those arising under Directive 96/9/EC of the
+     European Parliament and of the Council of 11 March 1996 on the legal
+     protection of databases, and under any national implementation
+     thereof, including any amended or successor version of such
+     directive); and
+vii. other similar, equivalent or corresponding rights throughout the
+     world based on applicable law or treaty, and any national
+     implementations thereof.
+
+2. Waiver. To the greatest extent permitted by, but not in contravention
+of, applicable law, Affirmer hereby overtly, fully, permanently,
+irrevocably and unconditionally waives, abandons, and surrenders all of
+Affirmer's Copyright and Related Rights and associated claims and causes
+of action, whether now known or unknown (including existing as well as
+future claims and causes of action), in the Work (i) in all territories
+worldwide, (ii) for the maximum duration provided by applicable law or
+treaty (including future time extensions), (iii) in any current or future
+medium and for any number of copies, and (iv) for any purpose whatsoever,
+including without limitation commercial, advertising or promotional
+purposes (the "Waiver"). Affirmer makes the Waiver for the benefit of each
+member of the public at large and to the detriment of Affirmer's heirs and
+successors, fully intending that such Waiver shall not be subject to
+revocation, rescission, cancellation, termination, or any other legal or
+equitable action to disrupt the quiet enjoyment of the Work by the public
+as contemplated by Affirmer's express Statement of Purpose.
+
+3. Public License Fallback. Should any part of the Waiver for any reason
+be judged legally invalid or ineffective under applicable law, then the
+Waiver shall be preserved to the maximum extent permitted taking into
+account Affirmer's express Statement of Purpose. In addition, to the
+extent the Waiver is so judged Affirmer hereby grants to each affected
+person a royalty-free, non transferable, non sublicensable, non exclusive,
+irrevocable and unconditional license to exercise Affirmer's Copyright and
+Related Rights in the Work (i) in all territories worldwide, (ii) for the
+maximum duration provided by applicable law or treaty (including future
+time extensions), (iii) in any current or future medium and for any number
+of copies, and (iv) for any purpose whatsoever, including without
+limitation commercial, advertising or promotional purposes (the
+"License"). The License shall be deemed effective as of the date CC0 was
+applied by Affirmer to the Work. Should any part of the License for any
+reason be judged legally invalid or ineffective under applicable law, such
+partial invalidity or ineffectiveness shall not invalidate the remainder
+of the License, and in such case Affirmer hereby affirms that he or she
+will not (i) exercise any of his or her remaining Copyright and Related
+Rights in the Work or (ii) assert any associated claims and causes of
+action with respect to the Work, in either case contrary to Affirmer's
+express Statement of Purpose.
+
+4. Limitations and Disclaimers.
+
+ a. No trademark or patent rights held by Affirmer are waived, abandoned,
+    surrendered, licensed or otherwise affected by this document.
+ b. Affirmer offers the Work as-is and makes no representations or
+    warranties of any kind concerning the Work, express, implied,
+    statutory or otherwise, including without limitation warranties of
+    title, merchantability, fitness for a particular purpose, non
+    infringement, or the absence of latent or other defects, accuracy, or
+    the present or absence of errors, whether or not discoverable, all to
+    the greatest extent permissible under applicable law.
+ c. Affirmer disclaims responsibility for clearing rights of other persons
+    that may apply to the Work or any use thereof, including without
+    limitation any person's Copyright and Related Rights in the Work.
+    Further, Affirmer disclaims responsibility for obtaining any necessary
+    consents, permissions or other rights required for any use of the
+    Work.
+ d. Affirmer understands and acknowledges that Creative Commons is not a
+    party to this document and has no duty or obligation with respect to
+    this CC0 or use of the Work.
diff --git a/basics/include/__typedef_clock_t.h b/basics/include/__typedef_clock_t.h
new file mode 100644
index 0000000..e7f0bbb
--- /dev/null
+++ b/basics/include/__typedef_clock_t.h
@@ -0,0 +1,2 @@
+/* Define this as a 64-bit signed integer to avoid wraparounds. */
+typedef long long clock_t;
diff --git a/basics/include/__typedef_time_t.h b/basics/include/__typedef_time_t.h
new file mode 100644
index 0000000..78763e1
--- /dev/null
+++ b/basics/include/__typedef_time_t.h
@@ -0,0 +1,2 @@
+/* Define this as a 64-bit signed integer to avoid the 2038 bug. */
+typedef long long time_t;
diff --git a/basics/include/stdlib.h b/basics/include/stdlib.h
new file mode 100644
index 0000000..ae90326
--- /dev/null
+++ b/basics/include/stdlib.h
@@ -0,0 +1,22 @@
+#ifndef __wasm_sysroot_stdlib_h
+#define __wasm_sysroot_stdlib_h
+
+#define __need_size_t
+#define __need_wchar_t
+#define __need_NULL
+#include <stddef.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void *malloc(size_t size);
+void free(void *ptr);
+void *calloc(size_t nmemb, size_t size);
+void *realloc(void *ptr, size_t size);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/basics/include/string.h b/basics/include/string.h
new file mode 100644
index 0000000..b218bbe
--- /dev/null
+++ b/basics/include/string.h
@@ -0,0 +1,20 @@
+#ifndef __wasm_sysroot_string_h
+#define __wasm_sysroot_string_h
+
+#define __need_size_t
+#define __need_NULL
+#include <stddef.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void *memcpy(void *dst, const void *src, size_t n);
+void *memmove(void *dst, const void *src, size_t n);
+void *memset(void *dst, int c, size_t n);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/basics/include/sys/types.h b/basics/include/sys/types.h
new file mode 100644
index 0000000..0241800
--- /dev/null
+++ b/basics/include/sys/types.h
@@ -0,0 +1,17 @@
+#ifndef __wasm_sysroot_sys_types_h
+#define __wasm_sysroot_sys_types_h
+
+#define __need_size_t
+#include <stddef.h>
+
+#include <__typedef_clock_t.h>
+#include <__typedef_time_t.h>
+
+/* Define these as 64-bit signed integers to support files larger than 2 GiB. */
+typedef long long blksize_t;
+typedef long long off_t;
+
+/* This is defined to be the same size as size_t. */
+typedef long ssize_t;
+
+#endif
diff --git a/basics/include/time.h b/basics/include/time.h
new file mode 100644
index 0000000..5046455
--- /dev/null
+++ b/basics/include/time.h
@@ -0,0 +1,10 @@
+#ifndef __wasm_sysroot_time_h
+#define __wasm_sysroot_time_h
+
+#define __need_size_t
+#define __need_NULL
+#include <stddef.h>
+
+#include <__typedef_time_t.h>
+
+#endif
diff --git a/basics/include/wchar.h b/basics/include/wchar.h
new file mode 100644
index 0000000..a6fe1dc
--- /dev/null
+++ b/basics/include/wchar.h
@@ -0,0 +1,9 @@
+#ifndef __wasm_sysroot_wchar_h
+#define __wasm_sysroot_wchar_h
+
+#define __need_size_t
+#define __need_wchar_t
+#define __need_NULL
+#include <stddef.h>
+
+#endif
diff --git a/basics/libc/crt1.s b/basics/libc/crt1.s
new file mode 100644
index 0000000..996cee9
--- /dev/null
+++ b/basics/libc/crt1.s
@@ -0,0 +1 @@
+# Empty.
diff --git a/basics/libc/string.c b/basics/libc/string.c
new file mode 100644
index 0000000..77d7201
--- /dev/null
+++ b/basics/libc/string.c
@@ -0,0 +1,41 @@
+#include <string.h>
+#include <stdint.h>
+
+static void *copy_forward(void *restrict dst, const void *restrict src, size_t n) {
+    char *d = (char *)dst;
+    const char *s = (const char *)src;
+    while (n-- != 0) {
+        *d++ = *s++;
+    }
+    return dst;
+}
+
+static void *copy_backward(void *restrict dst, const void *restrict src, size_t n) {
+    char *d = (char *)dst;
+    const char *s = (const char *)src;
+    d += n;
+    s += n;
+    while (n-- != 0) {
+        *--d = *--s;
+    }
+    return dst;
+}
+
+void *memcpy(void *restrict dst, const void *restrict src, size_t n) {
+    return copy_forward(dst, src, n);
+}
+
+void *memmove(void *dst, const void *src, size_t n) {
+    if ((uintptr_t)dst - (uintptr_t)src >= n) {
+        return copy_forward(dst, src, n);
+    }
+    return copy_backward(dst, src, n);
+}
+
+void *memset(void *restrict dst, int c, size_t n) {
+    char *d = (char *)dst;
+    while (n-- != 0) {
+        *d++ = c;
+    }
+    return dst;
+}