build system: use pkg-config to look up selinux libs

Newer versions of libselinux has started linking against more libs.
Rather than continuing hardcoding things, switch to using pkg-config
to query for its dependencies.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>

diff --git a/Makefile b/Makefile
index b2e9477..8995ff5 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -297,6 +297,7 @@ NM          = $(CROSS_COMPILE)nm
 STRIP          = $(CROSS_COMPILE)strip
 OBJCOPY                = $(CROSS_COMPILE)objcopy
 OBJDUMP                = $(CROSS_COMPILE)objdump
+PKG_CONFIG     ?= $(CROSS_COMPILE)pkg-config
 AWK            = awk
 GENKSYMS       = scripts/genksyms/genksyms
 DEPMOD         = /sbin/depmod

diff --git a/Makefile.flags b/Makefile.flags
index e77c0e5..307afa7 100644 (file)
--- a/Makefile.flags
+++ b/Makefile.flags
@@ -78,6 +78,12 @@ ARCH_FPIC ?= -fpic
 ARCH_FPIE ?= -fpie
 ARCH_PIE ?= -pie
 
+# Usage: $(eval $(call pkg_check_modules,VARIABLE-PREFIX,MODULES))
+define pkg_check_modules
+$(1)_CFLAGS := $(shell $(PKG_CONFIG) $(PKG_CONFIG_FLAGS) --cflags $(2))
+$(1)_LIBS := $(shell $(PKG_CONFIG) $(PKG_CONFIG_FLAGS) --libs $(2))
+endef
+
 ifeq ($(CONFIG_BUILD_LIBBUSYBOX),y)
 # on i386: 14% smaller libbusybox.so
 # (code itself is 9% bigger, we save on relocs/PLT/GOT)
@@ -89,6 +95,7 @@ endif
 
 ifeq ($(CONFIG_STATIC),y)
 CFLAGS_busybox += -static
+PKG_CONFIG_FLAGS += --static
 endif
 
 ifeq ($(CONFIG_PIE),y)
@@ -131,7 +138,10 @@ LDLIBS += pam pam_misc pthread
 endif
 
 ifeq ($(CONFIG_SELINUX),y)
-LDLIBS += selinux sepol
+SELINUX_PC_MODULES = libselinux libsepol
+$(eval $(call pkg_check_modules,SELINUX,$(SELINUX_PC_MODULES)))
+CPPFLAGS += $(SELINUX_CFLAGS)
+LDLIBS += $(if $(SELINUX_LIBS),$(SELINUX_LIBS:-l%=%),$(SELINUX_PC_MODULES:lib%=%))
 endif
 
 ifeq ($(CONFIG_EFENCE),y)