remove MANYLINUX option now that dockcross declares it

.travis.yml

@@ -87,7 +87,7 @@ script:
     ./build/src/unit_tests_runner;
   fi
 - if [[ "${BUILD_TARGET}" = "manylinux1-x64" ]]; then
-    ./dockcross-manylinux1-x64 cmake -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=build/manylinux1-x64/install -DBUILD_BACKEND=ON -DBUILD_SHARED_LIBS=OFF -DMANYLINUX=TRUE -Bbuild/manylinux1-x64 -H.;
+    ./dockcross-manylinux1-x64 cmake -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=build/manylinux1-x64/install -DBUILD_BACKEND=ON -DBUILD_SHARED_LIBS=OFF -Bbuild/manylinux1-x64 -H.;
     ./dockcross-manylinux1-x64 cmake --build build/manylinux1-x64 --target install;
   fi
 - if [[ "${BUILD_TARGET}" = "osx_build" ]]; then

CMakeLists.txt

@@ -5,7 +5,6 @@ project(mavsdk_superbuild)
 option(SUPERBUILD "Build dependencies" ON)
 option(BUILD_BACKEND "Build gRPC backend server" OFF)
 option(BUILD_SHARED_LIBS "Build core as shared libraries instead of static ones" ON)
-option(MANYLINUX "Build for manylinux. Required because gRPC doesn't detect it automatically." FALSE)
 
 set(DEPS_BUILD_PATH "${PROJECT_BINARY_DIR}/third_party" CACHE PATH "Install path for the dependencies. Ignored if SUPERBUILD=OFF.")
 set(DEPS_INSTALL_PATH "${DEPS_BUILD_PATH}/install" CACHE PATH "Install path for the dependencies. Ignored if SUPERBUILD=OFF.")

third_party/cmake/build_target.cmake

@@ -19,7 +19,6 @@ function(build_target TARGET_NAME)
             "-DCMAKE_PREFIX_PATH=${CMAKE_PREFIX_PATH}"
             "-DCMAKE_INSTALL_PREFIX=${TARGET_INSTALL_DIR}"
             "-DCMAKE_TOOLCHAIN_FILE=${CMAKE_TOOLCHAIN_FILE}"
-            "-DMANYLINUX=${MANYLINUX}"
             "-DANDROID_ABI=${ANDROID_ABI}"
             "-DANDROID_STL=${ANDROID_STL}"
             "-DANDROID_PLATFORM=${ANDROID_PLATFORM}"

third_party/grpc/CMakeLists.txt

@@ -40,7 +40,7 @@ elseif(IOS)
         "-DPLATFORM=${PLATFORM}"
         "-DgRPC_BUILD_CODEGEN=OFF"
         )
-elseif(MANYLINUX)
+elseif(MANYLINUX1)
     list(APPEND CMAKE_ARGS
         "-DCMAKE_CXX_FLAGS=-DGPR_MANYLINUX1=1"
         )