Add POSIX regex sources when needed

Windows doesn't support POSIX regex, so we need to include it
ourselves. The sources come from git, which in turn took them from
gawk.

CMakeLists.txt

@@ -28,6 +28,11 @@ FILE(GLOB SRC_HTTP deps/http-parser/*.c)
 
 IF (NOT WIN32)
 	FIND_PACKAGE(ZLIB)
+ELSE()
+	# Windows doesn't understand POSIX regex on its own
+	INCLUDE_DIRECTORIES(deps/regex)
+	SET(SRC_REGEX deps/regex/regex.c)
+	ADD_DEFINITIONS(-DGAWK -DNO_MBSUPPORT)
 ENDIF()
 
 IF (ZLIB_FOUND)
@@ -99,7 +104,7 @@ ELSE()
 ENDIF ()
 
 # Compile and link libgit2
-ADD_LIBRARY(git2 ${SRC} ${SRC_ZLIB} ${SRC_HTTP} ${WIN_RC})
+ADD_LIBRARY(git2 ${SRC} ${SRC_ZLIB} ${SRC_HTTP} ${SRC_REGEX} ${WIN_RC})
 
 IF (WIN32)
 	TARGET_LINK_LIBRARIES(git2 ws2_32)
@@ -130,7 +135,7 @@ IF (BUILD_TESTS)
 	INCLUDE_DIRECTORIES(tests)
 	FILE(GLOB SRC_TEST tests/t??-*.c)
 
-	ADD_EXECUTABLE(libgit2_test tests/test_main.c tests/test_lib.c tests/test_helpers.c ${SRC} ${SRC_TEST} ${SRC_ZLIB} ${SRC_HTTP})
+	ADD_EXECUTABLE(libgit2_test tests/test_main.c tests/test_lib.c tests/test_helpers.c ${SRC} ${SRC_TEST} ${SRC_ZLIB} ${SRC_HTTP} ${SRC_REGEX})
 	TARGET_LINK_LIBRARIES(libgit2_test ${CMAKE_THREAD_LIBS_INIT})
 	IF (WIN32)
 		TARGET_LINK_LIBRARIES(libgit2_test ws2_32)
@@ -158,7 +163,7 @@ IF (BUILD_CLAR)
 		DEPENDS ${CLAR_PATH}/clar ${SRC_TEST}
 		WORKING_DIRECTORY ${CLAR_PATH}
 	)
-	ADD_EXECUTABLE(libgit2_clar ${SRC} ${CLAR_PATH}/clar_main.c ${SRC_TEST} ${SRC_ZLIB} ${SRC_HTTP})
+	ADD_EXECUTABLE(libgit2_clar ${SRC} ${CLAR_PATH}/clar_main.c ${SRC_TEST} ${SRC_ZLIB} ${SRC_HTTP} ${SRC_REGEX})
 	TARGET_LINK_LIBRARIES(libgit2_clar ${CMAKE_THREAD_LIBS_INIT})
 	IF (WIN32)
 		TARGET_LINK_LIBRARIES(libgit2_clar ws2_32)

deps/regex/regex.c

+/* Extended regular expression matching and search library.
+   Copyright (C) 2002, 2003, 2005 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Isamu Hasegawa <isamu@yamato.ibm.com>.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+   02110-1301 USA.  */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+/* Make sure noone compiles this code with a C++ compiler.  */
+#ifdef __cplusplus
+# error "This is C code, use a C compiler"
+#endif
+
+#ifdef _LIBC
+/* We have to keep the namespace clean.  */
+# define regfree(preg) __regfree (preg)
+# define regexec(pr, st, nm, pm, ef) __regexec (pr, st, nm, pm, ef)
+# define regcomp(preg, pattern, cflags) __regcomp (preg, pattern, cflags)
+# define regerror(errcode, preg, errbuf, errbuf_size) \
+	__regerror(errcode, preg, errbuf, errbuf_size)
+# define re_set_registers(bu, re, nu, st, en) \
+	__re_set_registers (bu, re, nu, st, en)
+# define re_match_2(bufp, string1, size1, string2, size2, pos, regs, stop) \
+	__re_match_2 (bufp, string1, size1, string2, size2, pos, regs, stop)
+# define re_match(bufp, string, size, pos, regs) \
+	__re_match (bufp, string, size, pos, regs)
+# define re_search(bufp, string, size, startpos, range, regs) \
+	__re_search (bufp, string, size, startpos, range, regs)
+# define re_compile_pattern(pattern, length, bufp) \
+	__re_compile_pattern (pattern, length, bufp)
+# define re_set_syntax(syntax) __re_set_syntax (syntax)
+# define re_search_2(bufp, st1, s1, st2, s2, startpos, range, regs, stop) \
+	__re_search_2 (bufp, st1, s1, st2, s2, startpos, range, regs, stop)
+# define re_compile_fastmap(bufp) __re_compile_fastmap (bufp)
+
+# include "../locale/localeinfo.h"
+#endif
+
+#if defined (_MSC_VER)
+#include <stdio.h> /* for size_t */
+#endif
+
+/* On some systems, limits.h sets RE_DUP_MAX to a lower value than
+   GNU regex allows.  Include it before <regex.h>, which correctly
+   #undefs RE_DUP_MAX and sets it to the right value.  */
+#include <limits.h>
+
+#ifdef GAWK
+#undef alloca
+#define alloca alloca_is_bad_you_should_never_use_it
+#endif
+#include <regex.h>
+#include "regex_internal.h"
+
+#include "regex_internal.c"
+#ifdef GAWK
+#define bool int
+#define true (1)
+#define false (0)
+#endif
+#include "regcomp.c"
+#include "regexec.c"
+
+/* Binary backward compatibility.  */
+#if _LIBC
+# include <shlib-compat.h>
+# if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_3)
+link_warning (re_max_failures, "the 're_max_failures' variable is obsolete and will go away.")
+int re_max_failures = 2000;
+# endif
+#endif