Minor improvements to Windows support

.gitignore

@@ -1,4 +1,5 @@
 *.a
+*.exe
 *.html
 *.o
 *.xml

configure.ac

@@ -10,7 +10,7 @@ AC_CONFIG_HEADER(config.h)
 AC_CANONICAL_HOST
 
 case $host in
-    *mingw32* | *cygwin* | *wince* | *mingwce*)
+    *mingw32* | *mingw64* | *cygwin* | *wince* | *mingwce*)
         windows_os=yes
         AC_DEFINE(_WIN32_WINNT,0x0600, Windows Vista or newer is required)
         ;;

test/test_util.c

@@ -60,6 +60,20 @@ TEST(common_dir_prefix_length)
 
 TEST(get_relative_path)
 {
+#ifdef _WIN32
+	CHECK_STR_EQ_FREE2("a", get_relative_path("C:/doesn't matter", "a"));
+	CHECK_STR_EQ_FREE2("a/b", get_relative_path("C:/doesn't matter", "a/b"));
+	CHECK_STR_EQ_FREE2(".", get_relative_path("C:/a", "C:/a"));
+	CHECK_STR_EQ_FREE2("..", get_relative_path("C:/a/b", "C:/a"));
+	CHECK_STR_EQ_FREE2("b", get_relative_path("C:/a", "C:/a/b"));
+	CHECK_STR_EQ_FREE2("b/c", get_relative_path("C:/a", "C:/a/b/c"));
+	CHECK_STR_EQ_FREE2("../c", get_relative_path("C:/a/b", "C:/a/c"));
+	CHECK_STR_EQ_FREE2("../c/d", get_relative_path("C:/a/b", "C:/a/c/d"));
+	CHECK_STR_EQ_FREE2("../../c/d", get_relative_path("C:/a/b/c", "C:/a/c/d"));
+	CHECK_STR_EQ_FREE2("../..", get_relative_path("C:/a/b", "C:/"));
+	CHECK_STR_EQ_FREE2("../../c", get_relative_path("C:/a/b", "C:/c"));
+	CHECK_STR_EQ_FREE2("a/b", get_relative_path("C:/", "C:/a/b"));
+#else
 	CHECK_STR_EQ_FREE2("a", get_relative_path("/doesn't matter", "a"));
 	CHECK_STR_EQ_FREE2("a/b", get_relative_path("/doesn't matter", "a/b"));
 	CHECK_STR_EQ_FREE2(".", get_relative_path("/a", "/a"));
@@ -72,6 +86,7 @@ TEST(get_relative_path)
 	CHECK_STR_EQ_FREE2("../..", get_relative_path("/a/b", "/"));
 	CHECK_STR_EQ_FREE2("../../c", get_relative_path("/a/b", "/c"));
 	CHECK_STR_EQ_FREE2("a/b", get_relative_path("/", "/a/b"));
+#endif
 }
 
 TEST(format_hash_as_string)

util.c

@@ -1342,13 +1342,20 @@ get_relative_path(const char *from, const char *to)
 	const char *p;
 	char *result;
 
-	assert(from && from[0] == '/');
+	assert(from && is_absolute_path(from));
 	assert(to);
 
-	if (!*to || *to != '/') {
+	if (!*to || !is_absolute_path(to)) {
 		return x_strdup(to);
 	}
 
+#ifdef _WIN32
+	// Both paths are absolute, drop the drive letters
+	assert(from[0] == to[0]); // Assume the same drive letter
+	from += 2;
+	to += 2;
+#endif
+
 	result = x_strdup("");
 	common_prefix_len = common_dir_prefix_length(from, to);
 	if (common_prefix_len > 0 || !str_eq(from, "/")) {