[flashrom] [PATCH 1/3] Let pkg-config work with cross-compilers.

[Stefan Tauner]

In cross-compiler setups pkg-config often needs some help to
determine the correct libraries. This can be done for example by
setting PKG_CONFIG_LIBDIR to point to the directory where the
cross-compile .pc files are located. If PKG_CONFIG_LIBDIR was not
set already outside of the Makefile we set it according to LIBS_BASE
and add the respective path to the linker's rpath. This makes it
possible to easily cross-compile by only setting CC and LIBS_BASE on
the command line.

This patch also removes the explicit default for LIBS_BASE again
because it does not play well with this change and was a bad idea to
begin with.

Signed-off-by: Stefan Tauner <stefan.tauner at alumni.tuwien.ac.at>
Acked-by: Stefan Tauner <stefan.tauner at alumni.tuwien.ac.at>
---
 Makefile | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/Makefile b/Makefile
index a36628c..b738e73 100644
--- a/Makefile
+++ b/Makefile
@@ -37,7 +37,6 @@ MANDIR  ?= $(PREFIX)/share/man
 CFLAGS  ?= -Os -Wall -Wshadow
 EXPORTDIR ?= .
 RANLIB  ?= ranlib
-LIBS_BASE ?= ..
 
 # The following parameter changes the default programmer that will be used if there is no -p/--programmer
 # argument given when running flashrom. The predefined setting does not enable any default so that every
@@ -65,8 +64,13 @@ ifeq ($(WARNERROR), yes)
 CFLAGS += -Werror
 endif
 
+ifdef LIBS_BASE
 CPPFLAGS += -I$(LIBS_BASE)/include
-LDFLAGS += -L$(LIBS_BASE)/lib
+LDFLAGS += -L$(LIBS_BASE)/lib -Wl,-rpath -Wl,$(LIBS_BASE)/lib
+ifndef PKG_CONFIG_LIBDIR
+	PKG_CONFIG_LIBDIR = $(LIBS_BASE)/lib/pkgconfig
+endif
+endif
 
 ###############################################################################
 # General OS-specific settings.
@@ -611,7 +615,7 @@ PROGRAMMER_OBJS += usbblaster_spi.o
 endif
 
 ifeq ($(NEED_FTDI), yes)
-FTDILIBS := $(shell pkg-config --libs libftdi 2>/dev/null || printf "%s" "-lftdi -lusb")
+FTDILIBS := $(shell ([ -n "$(PKG_CONFIG_LIBDIR)" ] && export PKG_CONFIG_LIBDIR="$(PKG_CONFIG_LIBDIR)" ); pkg-config --libs libftdi || printf "%s" "-lftdi -lusb")
 FEATURE_CFLAGS += $(shell LC_ALL=C grep -q "FT232H := yes" .features && printf "%s" "-D'HAVE_FT232H=1'")
 FEATURE_LIBS += $(shell LC_ALL=C grep -q "FTDISUPPORT := yes" .features && printf "%s" "$(FTDILIBS)")
 # We can't set NEED_USB here because that would transform libftdi auto-enabling
@@ -734,7 +738,7 @@ endif
 ifeq ($(NEED_USB), yes)
 CHECK_LIBUSB0 = yes
 FEATURE_CFLAGS += -D'NEED_USB=1'
-USBLIBS := $(shell pkg-config --libs libusb 2>/dev/null || printf "%s" "-lusb")
+USBLIBS := $(shell ([ -n "$(PKG_CONFIG_LIBDIR)" ] && export PKG_CONFIG_LIBDIR="$(PKG_CONFIG_LIBDIR)" ); pkg-config --libs libusb  || printf "%s" "-lusb")
 endif
 
 ifeq ($(CONFIG_PRINT_WIKI), yes)
-- 
Kind regards, Stefan Tauner