build: use full paths on compile/link targets

This makes the compile commands clearer when building in parallel (with
`make -j`) and ensures that `__FILE__` includes the full build-time path
(relative to the root of the repository) whenever it is referenced, such
as in failed assert() messages (currently the full path is only shown in
errExit() messages).  Example:

Before:

    firejail: main.c:100: main: Assertion `1 == 2' failed.
    Error src/firecfg/main.c:100: main: malloc: Cannot allocate memory

After:

    firejail: ../../src/firejail/main.c:100: main: Assertion `1 == 2' failed.
    Error ../../src/firecfg/main.c:100: main: malloc: Cannot allocate memory

Commands used to search and replace:

    $ git grep -Ilz '^MOD_DIR =' -- '*Makefile' | xargs -0 -I '{}' \
      sh -c "printf '%s\n' \"\$(sed -E \
        -e 's|^MOD_DIR = src/(.*)|MOD = \\1\\nMOD_DIR = \$(ROOT)/src/\$(MOD)|' \
        -e 's:^(PROG|SO) = [^.]+(\.so)?$:\\1 = \$(MOD_DIR)/\$(MOD)\2:' \
        '{}')\" >'{}'"
    $ git grep -Ilz '^HDRS :=' -- '*.mk' | xargs -0 -I '{}' \
      sh -c "printf '%s\n' \"\$(sed -E \
        -e 's|wildcard (\*\..)|wildcard \$(MOD_DIR)/\\1|' '{}')\" >'{}'"

Note: config.mk.in, src/fnettrace/Makefile and src/include/common.h were
edited manually.

This is a follow-up to #5871.

1 files changed, 1 insertions, 1 deletions

diff --git a/config.mk.in b/config.mk.in
index 958efdb34..493a1f96f 100644
--- a/config.mk.in
+++ b/config.mk.in
@@ -81,7 +81,7 @@ LDFLAGS=@LDFLAGS@
 # Project variables
 EXTRA_CFLAGS  =@EXTRA_CFLAGS@
 COMMON_CFLAGS = \
-        -ggdb -O2 -DVERSION='"$(VERSION)"' -DMOD_DIR='"$(MOD_DIR)"' \
+        -ggdb -O2 -DVERSION='"$(VERSION)"' \
         -Wall -Wextra $(HAVE_FATAL_WARNINGS) \
         -Wformat -Wformat-security \
         -fstack-protector-all -D_FORTIFY_SOURCE=2 \