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, 5 insertions, 4 deletions

diff --git a/src/fnettrace/Makefile b/src/fnettrace/Makefile
index 68a4cbdc0..2ad296d1d 100644
--- a/src/fnettrace/Makefile
+++ b/src/fnettrace/Makefile
@@ -2,12 +2,13 @@
 ROOT = ../..
 -include $(ROOT)/config.mk
 
-MOD_DIR = src/fnettrace
-PROG = fnettrace
+MOD = fnettrace
+MOD_DIR = $(ROOT)/src/$(MOD)
+PROG = $(MOD_DIR)/$(MOD)
 TARGET = $(PROG)
 
 include $(ROOT)/src/prog.mk
 
 all: $(TARGET) static-ip-map
-static-ip-map: static-ip-map.txt fnettrace
-        ./fnettrace --squash-map=static-ip-map.txt > static-ip-map
+static-ip-map: static-ip-map.txt $(PROG)
+        ./$(PROG) --squash-map=static-ip-map.txt > static-ip-map