Improve errExit error messages

Changes:

* Move msg to the end of errExit (right before perror(3p))
* Include the full file path (within the repository)
* Add "()" to function name for clarity

Before:

    Error malloc: main.c:123 main: Cannot allocate memory

After:

    Error src/firejail/main.c:123 main(): malloc: Cannot allocate memory

Note: This clarifies which is the exact file that the error message
comes from, as there are many source files with the same name.  For
example:

    $ git ls-files 'src/*/main.c' | wc -l
    20

1 files changed, 1 insertions, 1 deletions

diff --git a/config.mk.in b/config.mk.in
index f3c1f658c..c76ca1a98 100644
--- a/config.mk.in
+++ b/config.mk.in
@@ -83,7 +83,7 @@ LDFLAGS=@LDFLAGS@
 # Project variables
 EXTRA_CFLAGS  =@EXTRA_CFLAGS@
 COMMON_CFLAGS = \
-        -ggdb -O2 -DVERSION='"$(VERSION)"' \
+        -ggdb -O2 -DVERSION='"$(VERSION)"' -DMOD_DIR='"$(MOD_DIR)"' \
         -Wall -Wextra $(HAVE_FATAL_WARNINGS) \
         -Wformat -Wformat-security \
         -fstack-protector-all -D_FORTIFY_SOURCE=2 \