turn path macros into inline function

Use static inline functions instead of macros for has_dos_drive_prefix,
offset_1st_component, is_dir_sep and find_last_dir_sep in order to let
the compiler do type checking.

The definitions of offset_1st_component and is_dir_sep are switched
around because the former uses the latter.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

git-compat-util.h

@@ -267,19 +267,35 @@ extern char *gitbasename(char *);
 #endif
 
 #ifndef has_dos_drive_prefix
-#define has_dos_drive_prefix(path) 0
+static inline int git_has_dos_drive_prefix(const char *path)
+{
+	return 0;
+}
+#define has_dos_drive_prefix git_has_dos_drive_prefix
 #endif
 
-#ifndef offset_1st_component
-#define offset_1st_component(path) (is_dir_sep((path)[0]))
+#ifndef is_dir_sep
+static inline int git_is_dir_sep(int c)
+{
+	return c == '/';
+}
+#define is_dir_sep git_is_dir_sep
 #endif
 
-#ifndef is_dir_sep
-#define is_dir_sep(c) ((c) == '/')
+#ifndef offset_1st_component
+static inline int git_offset_1st_component(const char *path)
+{
+	return is_dir_sep(path[0]);
+}
+#define offset_1st_component git_offset_1st_component
 #endif
 
 #ifndef find_last_dir_sep
-#define find_last_dir_sep(path) strrchr(path, '/')
+static inline char *git_find_last_dir_sep(const char *path)
+{
+	return strrchr(path, '/');
+}
+#define find_last_dir_sep git_find_last_dir_sep
 #endif
 
 #if defined(__HP_cc) && (__HP_cc >= 61000)