exec_cmd.c: replace hard-coded path list with one from <paths.h>

The default executable path list used by exec_cmd.c is hard-coded to
be "/usr/local/bin:/usr/bin:/bin".  Use an appropriate value for the
system from <paths.h> when available.

Add HAVE_PATHS_H make variables and enable it on Linux, FreeBSD,
NetBSD, OpenBSD and GNU where it is known to exist for now. Somebody
else may want to do an autoconf support later.

Signed-off-by: Chris Webb <chris@arachsys.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Makefile

@@ -31,6 +31,9 @@ all::
 # Define EXPATDIR=/foo/bar if your expat header and library files are in
 # /foo/bar/include and /foo/bar/lib directories.
 #
+# Define HAVE_PATHS_H if you have paths.h and want to use the default PATH
+# it specifies.
+#
 # Define NO_D_INO_IN_DIRENT if you don't have d_ino in your struct dirent.
 #
 # Define NO_D_TYPE_IN_DIRENT if your platform defines DT_UNKNOWN but lacks
@@ -702,10 +705,12 @@ EXTLIBS =
 ifeq ($(uname_S),Linux)
 	NO_STRLCPY = YesPlease
 	NO_MKSTEMPS = YesPlease
+	HAVE_PATHS_H = YesPlease
 endif
 ifeq ($(uname_S),GNU/kFreeBSD)
 	NO_STRLCPY = YesPlease
 	NO_MKSTEMPS = YesPlease
+	HAVE_PATHS_H = YesPlease
 endif
 ifeq ($(uname_S),UnixWare)
 	CC = cc
@@ -832,6 +837,7 @@ ifeq ($(uname_S),FreeBSD)
 		NO_STRTOUMAX = YesPlease
 	endif
 	PYTHON_PATH = /usr/local/bin/python
+	HAVE_PATHS_H = YesPlease
 endif
 ifeq ($(uname_S),OpenBSD)
 	NO_STRCASESTR = YesPlease
@@ -840,6 +846,7 @@ ifeq ($(uname_S),OpenBSD)
 	NEEDS_LIBICONV = YesPlease
 	BASIC_CFLAGS += -I/usr/local/include
 	BASIC_LDFLAGS += -L/usr/local/lib
+	HAVE_PATHS_H = YesPlease
 endif
 ifeq ($(uname_S),NetBSD)
 	ifeq ($(shell expr "$(uname_R)" : '[01]\.'),2)
@@ -849,6 +856,7 @@ ifeq ($(uname_S),NetBSD)
 	BASIC_LDFLAGS += -L/usr/pkg/lib $(CC_LD_DYNPATH)/usr/pkg/lib
 	USE_ST_TIMESPEC = YesPlease
 	NO_MKSTEMPS = YesPlease
+	HAVE_PATHS_H = YesPlease
 endif
 ifeq ($(uname_S),AIX)
 	NO_STRCASESTR=YesPlease
@@ -869,6 +877,7 @@ ifeq ($(uname_S),GNU)
 	# GNU/Hurd
 	NO_STRLCPY=YesPlease
 	NO_MKSTEMPS = YesPlease
+	HAVE_PATHS_H = YesPlease
 endif
 ifeq ($(uname_S),IRIX)
 	NO_SETENV = YesPlease
@@ -1309,6 +1318,10 @@ else
 	LIB_OBJS += thread-utils.o
 endif
 
+ifdef HAVE_PATHS_H
+	BASIC_CFLAGS += -DHAVE_PATHS_H
+endif
+
 ifdef DIR_HAS_BSD_GROUP_SEMANTICS
 	COMPAT_CFLAGS += -DDIR_HAS_BSD_GROUP_SEMANTICS
 endif

exec_cmd.c

@@ -107,7 +107,7 @@ void setup_path(void)
 	if (old_path)
 		strbuf_addstr(&new_path, old_path);
 	else
-		strbuf_addstr(&new_path, "/usr/local/bin:/usr/bin:/bin");
+		strbuf_addstr(&new_path, _PATH_DEFPATH);
 
 	setenv("PATH", new_path.buf, 1);
 

git-compat-util.h

@@ -163,6 +163,13 @@ extern char *gitbasename(char *);
 #define PATH_SEP ':'
 #endif
 
+#ifdef HAVE_PATHS_H
+#include <paths.h>
+#endif
+#ifndef _PATH_DEFPATH
+#define _PATH_DEFPATH "/usr/local/bin:/usr/bin:/bin"
+#endif
+
 #ifndef STRIP_EXTENSION
 #define STRIP_EXTENSION ""
 #endif