host_apps: Add --no-as-needed to stop libmmal_vc_client being dropped

Some versions of GCC have --as-needed turned on by default.
The binding of libmmal_vc_client is such that the constructor
registers the supported components with the MMAL core, and nothing
calls into it directly. The linker can't tell this, decides
it is unused, and promptly drops it as a dependency - cue no
VideoCore components.

Adding --no-as-needed means that the linker leaves it alone.
It's not nice, but there doesn't appear to be a better solution.

See #178.

host_applications/android/apps/vidtex/CMakeLists.txt

@@ -1,6 +1,12 @@
 cmake_minimum_required(VERSION 2.8)
 
 SET(COMPILE_DEFINITIONS -Werror -Wall)
+
+# Set --no-as-needed to stop the linker discarding mmal_vc_client
+# as it can't see that the constructor registers a load of functionality
+# with the MMAL core.
+SET( CMAKE_EXE_LINKER_FLAGS "-Wl,--no-as-needed" )
+
 include_directories(${PROJECT_SOURCE_DIR}/host_applications/linux/libs/bcm_host/include)
 
 set (VIDTEX_SOURCES

host_applications/linux/apps/hello_pi/hello_mmal_encode/Makefile

@@ -1,6 +1,10 @@
 OBJS=mmal_encode.o
 BIN=hello_mmal_encode.bin
 LDFLAGS+=-lmmal -lmmal_core -lmmal_components -lmmal_util -lmmal_vc_client
+# Set --no-as-needed to stop the linker discarding mmal_vc_client
+# as it can't see that the constructor registers a load of functionality
+# with the MMAL core.
+LDFLAGS+=-Wl,--no-as-needed
 
 include ../Makefile.include
 

host_applications/linux/apps/raspicam/CMakeLists.txt

@@ -3,6 +3,11 @@
 
 SET(COMPILE_DEFINITIONS -Werror)
 
+# Set --no-as-needed to stop the linker discarding mmal_vc_client
+# as it can't see that the constructor registers a load of functionality
+# with the MMAL core.
+SET( CMAKE_EXE_LINKER_FLAGS "-Wl,--no-as-needed" )
+
 include_directories(${PROJECT_SOURCE_DIR}/host_applications/linux/libs/bcm_host/include)
 include_directories(${PROJECT_SOURCE_DIR}/host_applications/linux/apps/raspicam/)
 include_directories(${PROJECT_SOURCE_DIR}/host_applications/linux/libs/sm)