[PATCH] build: fix pointer arithmetic problem

[Weiping Pan <wpan redhat com>]

Commit bb363997edf9(build: add some more build-time warnings) triggers two
build errors.

1 -Wmissing-include-dirs
cc1: error: ../marshallers: No such file or directory [-Werror]
cc1: all warnings being treated as errors

When I remove "-Wmissing-include-dirs", the error disappears.
But I do not know why "../marshallers" is not created.

2 -Wpointer-arith
nm-logging.c: In function 'fallback_get_backtrace':
nm-logging.c:264:31: error: pointer of type 'void *' used in subtraction
[-Werror=pointer-arith]
nm-logging.c:270:31: error: pointer of type 'void *' used in subtraction
[-Werror=pointer-arith]
cc1: all warnings being treated as errors

Signed-off-by: Weiping Pan <wpan redhat com>
---
 m4/compiler_warnings.m4  |    2 +-
 src/logging/nm-logging.c |    4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/m4/compiler_warnings.m4 b/m4/compiler_warnings.m4
index 3037c58..7353f86 100644
--- a/m4/compiler_warnings.m4
+++ b/m4/compiler_warnings.m4
@@ -13,7 +13,7 @@ if test "$GCC" = "yes" -a "$set_more_warnings" != "no"; then
 		      -fno-strict-aliasing -Wno-unused-but-set-variable \
 		      -Wundef -Wimplicit-function-declaration \
 		      -Wpointer-arith -Winit-self \
-		      -Wmissing-include-dirs -Waggregate-return; do
+		      -Waggregate-return; do
 		SAVE_CFLAGS="$CFLAGS"
 		CFLAGS="$CFLAGS $option"
 		AC_MSG_CHECKING([whether gcc understands $option])
diff --git a/src/logging/nm-logging.c b/src/logging/nm-logging.c
index f54adcd..660990b 100644
--- a/src/logging/nm-logging.c
+++ b/src/logging/nm-logging.c
@@ -261,13 +261,13 @@ fallback_get_backtrace (void)
 			syslog (LOG_CRIT, "Frame %d: %s (%s+0x%lx) [%p]",
 			        i, name,
 			        info.dli_sname,
-			        (gulong)(frames[i] - info.dli_saddr),
+			        (gulong)frames[i] - (gulong)info.dli_saddr,
 			        frames[i]);
 		} else {
 			syslog (LOG_CRIT, "Frame %d: %s (%p+0x%lx) [%p]",
 			        i, name,
 			        info.dli_fbase,
-			        (gulong)(frames[i] - info.dli_saddr),
+			        (gulong)frames[i] - (gulong)info.dli_saddr,
 			        frames[i]);
 		}
 	}
-- 
1.7.7.6