makefiles: move extra deps into new MOD vars

To make the makefiles more similar.

That is, add the following new variables:

* MOD_HDRS
* MOD_SRCS
* MOD_OBJS

And move existing module-specific header and object dependencies into
`MOD_HDRS` and `MOD_OBJS`, respectively.  `MOD_SRCS` is added mostly for
symmetry/consistency.

Note: Use `MOD_` as a prefix instead of `EXTRA_` to avoid confusion, as
the latter is currently used for global variables (such as
`EXTRA_CFLAGS`), as opposed to module-specific variables.

Note2: Add them directly into the HDRS/SRCS/OBJS variables to avoid
cluttering the existing recipes with an extra variables unnecessarily.
This also allows, for example, referencing all of the object
dependencies with `$<` if `$(OBJS)` is the first dependency (at least in
GNU make).

Note3: Since HDRS/SRCS/OBJS use simple assignment (through `:=`), the
MOD variables should appear before including src/common.mk (or
src/so.mk).

1 files changed, 3 insertions, 3 deletions

diff --git a/src/common.mk b/src/common.mk
index c20aaf52f..2deace4f5 100644
--- a/src/common.mk
+++ b/src/common.mk
@@ -2,9 +2,9 @@
 #
 # Note: $(ROOT)/config.mk must be included before this file.
 
-HDRS := $(sort $(wildcard *.h))
-SRCS := $(sort $(wildcard *.c))
-OBJS := $(SRCS:.c=.o)
+HDRS := $(sort $(wildcard *.h)) $(MOD_HDRS)
+SRCS := $(sort $(wildcard *.c)) $(MOD_SRCS)
+OBJS := $(SRCS:.c=.o) $(MOD_OBJS)
 
 CFLAGS += -ggdb $(HAVE_FATAL_WARNINGS) -O2 -DVERSION='"$(VERSION)"' $(HAVE_GCOV)
 CFLAGS += -DPREFIX='"$(prefix)"' -DSYSCONFDIR='"$(sysconfdir)/firejail"' -DLIBDIR='"$(libdir)"' -DBINDIR='"$(bindir)"'   -DVARDIR='"/var/lib/firejail"'