Minor libdav1d's build script improvement

scripts/export-host-variables.sh

@@ -28,6 +28,8 @@ export CMAKE_EXECUTABLE=${ANDROID_SDK_HOME}/cmake/3.10.2.4988404/bin/cmake
 # Using Ninja from the Android SDK
 export NINJA_EXECUTABLE=${ANDROID_SDK_HOME}/cmake/3.10.2.4988404/bin/ninja
 # Using host Make, because Android NDK's Make (before r21) doesn't work properly in MSYS2 on Windows
-export MAKE_EXECUTABLE=make
-# Meson is used for libdav1d building
-export MESON_EXECUTABLE=meson
+export MAKE_EXECUTABLE=$(which make)
+# Meson is used for libdav1d building. Needs to be installed
+export MESON_EXECUTABLE=$(which meson)
+# Nasm is used for libdav1d building. Needs to be installed
+export NASM_EXECUTABLE=$(which nasm)

scripts/libdav1d/build.sh

@@ -8,6 +8,7 @@ c = '${FAM_CC}'
 cpp = '${FAM_CXX}'
 ar = '${FAM_AR}'
 strip = '${FAM_STRIP}'
+nasm = '${NASM_EXECUTABLE}'
 objcopy = '${FAM_OBJCOPY}'
 pkgconfig = '$(which pkg-config)'
 
@@ -29,7 +30,7 @@ BUILD_DIRECTORY=build/${ANDROID_ABI}
 
 rm -rf ${BUILD_DIRECTORY}
 
-meson . ${BUILD_DIRECTORY} \
+${MESON_EXECUTABLE} . ${BUILD_DIRECTORY} \
   --cross-file ${CROSS_FILE_NAME} \
   --default-library=static \
   -Denable_asm=true \
@@ -40,5 +41,5 @@ meson . ${BUILD_DIRECTORY} \
 
 cd ${BUILD_DIRECTORY}
 
-${NINJA_EXECUTABLE}
+${NINJA_EXECUTABLE} -j ${HOST_NPROC}
 ${NINJA_EXECUTABLE} install