Makefile: -lpthread may still be necessary when libc has only pthread stubs

Without this patch, systems that provide stubs for pthread functions
in libc, but which still require libpthread for full the pthread
implementation are not detected correctly.

Also, some systems require -pthread in CFLAGS for each compilation
unit for a successful link of an mt binary, which is also addressed by
this patch.

Signed-off-by: Gary V. Vaughan <gary@thewrittenword.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Makefile b/Makefile
index da0cfda3e8a5b8b04012862e66b84da34af680a6..f6085a52400a2f440cc174cdd8ab980c3c7a644d 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -294,6 +294,7 @@ RPMBUILD = rpmbuild
 TCL_PATH = tclsh
 TCLTK_PATH = wish
 PTHREAD_LIBS = -lpthread
+PTHREAD_CFLAGS =
 
 export TCL_PATH TCLTK_PATH
 
@@ -898,6 +899,8 @@ ifeq ($(uname_S),AIX)
        BASIC_CFLAGS += -D_LARGE_FILES
        ifeq ($(shell expr "$(uname_V)" : '[1234]'),1)
                NO_PTHREADS = YesPlease
+       else
+               PTHREAD_LIBS = -lpthread
        endif
 endif
 ifeq ($(uname_S),GNU)
@@ -1349,6 +1352,7 @@ endif
 ifdef NO_PTHREADS
        BASIC_CFLAGS += -DNO_PTHREADS
 else
+       BASIC_CFLAGS += $(PTHREAD_CFLAGS)
        EXTLIBS += $(PTHREAD_LIBS)
        LIB_OBJS += thread-utils.o
 endif

diff --git a/config.mak.in b/config.mak.in
index 7eb6f59eb1de2af9b59f9e596524f6ad751f82b8..d35f639d4c2d41c01efcef743795102c203763d1 100644 (file)
--- a/config.mak.in
+++ b/config.mak.in
@@ -57,4 +57,5 @@ NO_DEFLATE_BOUND=@NO_DEFLATE_BOUND@
 FREAD_READS_DIRECTORIES=@FREAD_READS_DIRECTORIES@
 SNPRINTF_RETURNS_BOGUS=@SNPRINTF_RETURNS_BOGUS@
 NO_PTHREADS=@NO_PTHREADS@
+PTHREAD_CFLAGS=@PTHREAD_CFLAGS@
 PTHREAD_LIBS=@PTHREAD_LIBS@

diff --git a/configure.ac b/configure.ac
index f4d7372ef8d7b45f9810d5f8bc191c71622a71f2..ad380b83d1921b9f9e1080a971a760ec4df96de3 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -802,7 +802,11 @@ AC_DEFUN([PTHREADTEST_SRC], [
 int main(void)
 {
        pthread_mutex_t test_mutex;
-       return (0);
+       int retcode = 0;
+       retcode |= pthread_mutex_init(&test_mutex,(void *)0);
+       retcode |= pthread_mutex_lock(&test_mutex);
+       retcode |= pthread_mutex_unlock(&test_mutex);
+       return retcode;
 }
 ])
 
@@ -819,7 +823,8 @@ if test -n "$USER_NOPTHREAD"; then
 # handle these separately since PTHREAD_CFLAGS could be '-lpthreads
 # -D_REENTRANT' or some such.
 elif test -z "$PTHREAD_CFLAGS"; then
-  for opt in -pthread -lpthread; do
+  threads_found=no
+  for opt in -mt -pthread -lpthread; do
      old_CFLAGS="$CFLAGS"
      CFLAGS="$opt $CFLAGS"
      AC_MSG_CHECKING([Checking for POSIX Threads with '$opt'])
@@ -827,11 +832,18 @@ elif test -z "$PTHREAD_CFLAGS"; then
        [AC_MSG_RESULT([yes])
                NO_PTHREADS=
                PTHREAD_LIBS="$opt"
+               PTHREAD_CFLAGS="$opt"
+               threads_found=yes
                break
        ],
        [AC_MSG_RESULT([no])])
       CFLAGS="$old_CFLAGS"
   done
+  if test $threads_found != yes; then
+    AC_CHECK_LIB([pthread], [pthread_create],
+       [PTHREAD_LIBS="-lpthread"],
+       [NO_PTHREADS=UnfortunatelyYes])
+  fi
 else
   old_CFLAGS="$CFLAGS"
   CFLAGS="$PTHREAD_CFLAGS $CFLAGS"
@@ -848,6 +860,7 @@ fi
 
 CFLAGS="$old_CFLAGS"
 
+AC_SUBST(PTHREAD_CFLAGS)
 AC_SUBST(PTHREAD_LIBS)
 AC_SUBST(NO_PTHREADS)