Avoid multiple PREFIX definitions

The short and sweet PREFIX can be confused when used in many places.

Rename both usages to better describe their purpose. EXEC_CMD_PREFIX is
used in full to disambiguate it from the nearby GIT_EXEC_PATH.

The PREFIX in sideband.c, while nominally independant of the exec_cmd
PREFIX, does reside within libgit[1], so the definitions would clash
when taken together with a PREFIX given on the command line for use by
exec_cmd.c.

Noticed when compiling Git for Windows using MSVC/Visual Studio [1] which
reports the conflict beteeen the command line definition and the
definition in sideband.c within the libgit project.

[1] the libgit functions are brought into a single sub-project
within the Visual Studio construction script provided in contrib,
and hence uses a single command for both exec_cmd.c and sideband.c.

Signed-off-by: Philip Oakley <philipoakley@iee.org>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Makefile

@@ -2261,7 +2261,7 @@ exec_cmd.sp exec_cmd.s exec_cmd.o: EXTRA_CPPFLAGS = \
 	'-DGIT_EXEC_PATH="$(gitexecdir_SQ)"' \
 	'-DGIT_LOCALE_PATH="$(localedir_relative_SQ)"' \
 	'-DBINDIR="$(bindir_relative_SQ)"' \
-	'-DPREFIX="$(prefix_SQ)"'
+	'-DFALLBACK_RUNTIME_PREFIX="$(prefix_SQ)"'
 
 builtin/init-db.sp builtin/init-db.s builtin/init-db.o: GIT-PREFIX
 builtin/init-db.sp builtin/init-db.s builtin/init-db.o: EXTRA_CPPFLAGS = \

exec_cmd.c

@@ -48,7 +48,7 @@ static const char *system_prefix(void)
 	    !(prefix = strip_path_suffix(executable_dirname, GIT_EXEC_PATH)) &&
 	    !(prefix = strip_path_suffix(executable_dirname, BINDIR)) &&
 	    !(prefix = strip_path_suffix(executable_dirname, "git"))) {
-		prefix = PREFIX;
+		prefix = FALLBACK_RUNTIME_PREFIX;
 		trace_printf("RUNTIME_PREFIX requested, "
 				"but prefix computation failed.  "
 				"Using static fallback '%s'.\n", prefix);
@@ -243,7 +243,7 @@ void git_resolve_executable_dir(const char *argv0)
  */
 static const char *system_prefix(void)
 {
-	return PREFIX;
+	return FALLBACK_RUNTIME_PREFIX;
 }
 
 /*

sideband.c

@@ -13,7 +13,7 @@
  * the remote died unexpectedly.  A flush() concludes the stream.
  */
 
-#define PREFIX "remote: "
+#define DISPLAY_PREFIX "remote: "
 
 #define ANSI_SUFFIX "\033[K"
 #define DUMB_SUFFIX "        "
@@ -49,7 +49,7 @@ int recv_sideband(const char *me, int in_stream, int out)
 		switch (band) {
 		case 3:
 			strbuf_addf(&outbuf, "%s%s%s", outbuf.len ? "\n" : "",
-				    PREFIX, buf + 1);
+				    DISPLAY_PREFIX, buf + 1);
 			retval = SIDEBAND_REMOTE_ERROR;
 			break;
 		case 2:
@@ -67,7 +67,7 @@ int recv_sideband(const char *me, int in_stream, int out)
 				int linelen = brk - b;
 
 				if (!outbuf.len)
-					strbuf_addstr(&outbuf, PREFIX);
+					strbuf_addstr(&outbuf, DISPLAY_PREFIX);
 				if (linelen > 0) {
 					strbuf_addf(&outbuf, "%.*s%s%c",
 						    linelen, b, suffix, *brk);
@@ -81,8 +81,8 @@ int recv_sideband(const char *me, int in_stream, int out)
 			}
 
 			if (*b)
-				strbuf_addf(&outbuf, "%s%s",
-					    outbuf.len ? "" : PREFIX, b);
+				strbuf_addf(&outbuf, "%s%s", outbuf.len ?
+					    "" : DISPLAY_PREFIX, b);
 			break;
 		case 1:
 			write_or_die(out, buf + 1, len);