package/rpi-userland: fix build with libexecinfo

Fix the following build failure raised on uclibc and musl since the
addition of libexecinfo package in commit
eea8ba446c10701a273432552108d80fb2224ef4:

/home/peko/autobuild/instance-1/output-1/host/opt/ext-toolchain/bin/../lib/gcc/arm-buildroot-linux-uclibcgnueabi/10.3.0/../../../../arm-buildroot-linux-uclibcgnueabi/bin/ld: ../../build/lib/libvcos.so: undefined reference to `backtrace_symbols'

Fixes:
 - http://autobuild.buildroot.org/results/93d3b8cc2ac5dfa9d4b44946c0b4d8171e8f52a1

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
(cherry picked from commit bc4cc27705de50356d7e9945e41bd989fdc56fe8)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/rpi-userland/0006-don-t-override-CMAKE_EXE_LINKER_FLAGS.patch

@@ -0,0 +1,58 @@
+From 87febf8b7b1c0a6d0ea1d26770d3665008d66fd2 Mon Sep 17 00:00:00 2001
+From: Fabrice Fontaine <fontaine.fabrice@gmail.com>
+Date: Fri, 25 Feb 2022 19:21:06 +0100
+Subject: [PATCH] don't override CMAKE_EXE_LINKER_FLAGS
+
+Don't override CMAKE_EXE_LINKER_FLAGS as it could be used by the user to
+pass additional flags such as -lexecinfo on musl and uclibc-ng
+
+Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
+[Upstream status: https://github.com/raspberrypi/userland/pull/719]
+---
+ host_applications/android/apps/vidtex/CMakeLists.txt | 2 +-
+ host_applications/linux/apps/raspicam/CMakeLists.txt | 2 +-
+ makefiles/cmake/arm-linux.cmake                      | 2 +-
+ 3 files changed, 3 insertions(+), 3 deletions(-)
+
+diff --git a/host_applications/android/apps/vidtex/CMakeLists.txt b/host_applications/android/apps/vidtex/CMakeLists.txt
+index e7206cc..16c64db 100644
+--- a/host_applications/android/apps/vidtex/CMakeLists.txt
++++ b/host_applications/android/apps/vidtex/CMakeLists.txt
+@@ -5,7 +5,7 @@ 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" )
++SET( CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -Wl,--no-as-needed" )
+ 
+ include_directories(${PROJECT_SOURCE_DIR}/host_applications/linux/libs/bcm_host/include)
+ 
+diff --git a/host_applications/linux/apps/raspicam/CMakeLists.txt b/host_applications/linux/apps/raspicam/CMakeLists.txt
+index e6bd373..2f72eb2 100644
+--- a/host_applications/linux/apps/raspicam/CMakeLists.txt
++++ b/host_applications/linux/apps/raspicam/CMakeLists.txt
+@@ -6,7 +6,7 @@ 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" )
++SET( CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -Wl,--no-as-needed" )
+ 
+ include_directories(${PROJECT_SOURCE_DIR}/host_applications/linux/libs/bcm_host/include)
+ include_directories(${PROJECT_SOURCE_DIR}/host_applications/linux/apps/raspicam/)
+diff --git a/makefiles/cmake/arm-linux.cmake b/makefiles/cmake/arm-linux.cmake
+index 957846a..e172282 100644
+--- a/makefiles/cmake/arm-linux.cmake
++++ b/makefiles/cmake/arm-linux.cmake
+@@ -93,7 +93,7 @@ if(ANDROID)
+     set(CMAKE_SHARED_LINKER_FLAGS "-nostdlib ${ANDROID_CRTBEGIN} -Wl,-Bdynamic -Wl,-T${ANDROID_LDSCRIPTS}/armelf.x")
+ 
+     link_directories(${ANDROID_LIBS})
+-    set(CMAKE_EXE_LINKER_FLAGS "-nostdlib ${ANDROID_CRTBEGIN} -nostdlib -Wl,-z,noexecstack") 
++    set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -nostdlib ${ANDROID_CRTBEGIN} -nostdlib -Wl,-z,noexecstack") 
+     set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -Wl,-dynamic-linker,/system/bin/linker -Wl,-rpath,${CMAKE_INSTALL_PREFIX}/lib")
+     set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -Wl,-T${ANDROID_LDSCRIPTS}/armelf.x -Wl,--gc-sections")
+     set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -Wl,-z,nocopyreloc -Wl,-z,noexecstack -Wl,--fix-cortex-a8 -Wl,--no-undefined")
+-- 
+2.34.1
+

package/rpi-userland/rpi-userland.mk

@@ -13,6 +13,11 @@ RPI_USERLAND_CONF_OPTS = -DVMCS_INSTALL_PREFIX=/usr
 
 RPI_USERLAND_PROVIDES = libegl libgles libopenmax libopenvg
 
+ifeq ($(BR2_PACKAGE_LIBEXECINFO),y)
+RPI_USERLAND_DEPENDENCIES += libexecinfo
+RPI_USERLAND_CONF_OPTS += -DCMAKE_EXE_LINKER_FLAGS=-lexecinfo
+endif
+
 ifeq ($(BR2_PACKAGE_RPI_USERLAND_HELLO),y)
 
 RPI_USERLAND_CONF_OPTS += -DALL_APPS=ON