package/libdcadec: Add -fPIC to static build, enable shared build

Build errors occured due to libdcadec being linked statically.

Fixes
http://autobuild.buildroot.net/results/a19/a19023e094cbed491444665d6839a9e65a8eee6c/
http://autobuild.buildroot.net/results/98d/98dde028d1d6199f05c904b498bc39bbaa112aa6/
http://autobuild.buildroot.net/results/4ff/4ffcae6cae419df35e8ca29d429ee178bcf31882/
http://autobuild.buildroot.net/results/8ce/8ced16874255ace4923f6b8888c3fca07f28b804/

---
v2: removed -fPIC for static build (Thomas, Samuel)

 package/libdcadec/libdcadec.mk | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

index 76862a6..dff67b5 100644
@@ -10,19 +10,24 @@ LIBDCADEC_LICENSE = LGPLv2.1+
 LIBDCADEC_LICENSE_FILES = COPYING.LGPLv2.1
 LIBDCADEC_INSTALL_STAGING = YES
 
+ifneq ($(BR2_STATIC_LIBS),y)
+LIBDCADEC_SHARED = CONFIG_SHARED=1
+endif
+
 define LIBDCADEC_BUILD_CMDS
 	$(TARGET_MAKE_ENV) $(MAKE) $(TARGET_CONFIGURE_OPTS) \
-		CFLAGS="$(TARGET_CFLAGS) -std=gnu99" -C $(@D)
+		CFLAGS="$(TARGET_CFLAGS) -std=gnu99" \
+		$(LIBDCADEC_SHARED) -C $(@D)
 endef
 
 define LIBDCADEC_INSTALL_STAGING_CMDS
 	$(TARGET_MAKE_ENV) $(MAKE) $(TARGET_CONFIGURE_OPTS) -C $(@D) \
-		DESTDIR=$(STAGING_DIR) PREFIX=/usr install
+		$(LIBDCADEC_SHARED) DESTDIR=$(STAGING_DIR) PREFIX=/usr install
 endef
 
 define LIBDCADEC_INSTALL_TARGET_CMDS
 	$(TARGET_MAKE_ENV) $(MAKE) $(TARGET_CONFIGURE_OPTS) -C $(@D) \
-		DESTDIR=$(TARGET_DIR) PREFIX=/usr install
+		$(LIBDCADEC_SHARED) DESTDIR=$(TARGET_DIR) PREFIX=/usr install
 endef
 
 $(eval $(generic-package))

2.6.1

Bernd,

Thanks for the new version!

The title of the commit now seems a bit odd, since you're no longer adding -fPIC.

Can you be more verbose in your commit log, to explain what's going on? At the bare minimum, something like:

"""
The libdcadec package currently only builds a static library, which is naturally built without -fPIC (since this is generally not needed for static libraries).

However, when the generated static library gets used inside a larger dynamic library, such as ffmpeg's one, the link fails, since we're trying to include in a shared library non-PIC code.

To solve this, this commit changes the way the libdcadec library is built to make sure a shared variant of the library gets built when appropriate. This way, ffmpeg has a PIC-enabled libdcadec library to link with.
"""

Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com