fix: don't override system CMAKE_EXE_LINKER_FLAGS and don't set -fPIE…

… for shared libraries

- Append to CMAKE_EXE_LINKER_FLAGS instead of overriding it.
- `-fPIE` is invalid for shared libraries. Removing it here fixes building for Arch. Please use --enable-default-pie for gcc instead of inserting PIE flags to every package.

src/CMakeLists.txt

@@ -102,13 +102,13 @@ install (FILES ${CMAKE_SOURCE_DIR}/com.deepin.movie.service DESTINATION ${CMAKE_
 
 # 加速编译优化参数
 if (CMAKE_HOST_SYSTEM_PROCESSOR MATCHES "mips64")
-    SET(CMAKE_CXX_FLAGS "$ENV{CXXFLAGS} -O3 -ftree-vectorize -march=loongson3a -mhard-float -mno-micromips -mno-mips16 -flax-vector-conversions -mloongson-ext2 -mloongson-mmi -Wl,--as-needed -fPIE -z noexecstack")
-    SET(CMAKE_C_FLAGS "$ENV{CFLAGS} -O3 -ftree-vectorize -march=loongson3a -mhard-float -mno-micromips -mno-mips16 -flax-vector-conversions -mloongson-ext2 -mloongson-mmi -z noexecstack")
-    SET(CMAKE_EXE_LINKER_FLAGS "-pie")
+    SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -O3 -ftree-vectorize -march=loongson3a -mhard-float -mno-micromips -mno-mips16 -flax-vector-conversions -mloongson-ext2 -mloongson-mmi -Wl,--as-needed -z noexecstack")
+    SET(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -O3 -ftree-vectorize -march=loongson3a -mhard-float -mno-micromips -mno-mips16 -flax-vector-conversions -mloongson-ext2 -mloongson-mmi -z noexecstack")
+    SET(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -pie")
 else()
-    SET(CMAKE_CXX_FLAGS "$ENV{CXXFLAGS} -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2 -std=c++14 -O3 -DNDEBUG -fPIC -Wl,--as-needed -fPIE")
-    SET(CMAKE_C_FLAGS "$ENV{CFLAGS} -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2 -std=c++14 -O3 -DNDEBUG -fPIC")
-    SET(CMAKE_EXE_LINKER_FLAGS "-pie")
+    SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2 -std=c++14 -O3 -DNDEBUG -fPIC -Wl,--as-needed")
+    SET(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2 -std=c++14 -O3 -DNDEBUG -fPIC")
+    SET(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -pie")
 endif()
 
 add_subdirectory(libdmr)