Use -mthumb when building for arm

diff --git a/build-package.sh b/build-package.sh
index 0a05431..f0f1190 100755 (executable)
--- a/build-package.sh
+++ b/build-package.sh
@@ -462,10 +462,10 @@ termux_step_setup_toolchain() {
        # and no longer remove DT_RUNPATH in termux-elf-cleaner.
 
        if [ "$TERMUX_ARCH" = "arm" ]; then
        # and no longer remove DT_RUNPATH in termux-elf-cleaner.
 
        if [ "$TERMUX_ARCH" = "arm" ]; then

-               CFLAGS+=" -march=armv7-a -mfpu=neon -mfloat-abi=softfp"
-               # "first flag instructs the linker to pick libgcc.a, libgcov.a, and
-               # crt*.o, which are tailored for armv7-a"
-               # - https://developer.android.com/ndk/guides/standalone_toolchain.html
+               # https://developer.android.com/ndk/guides/standalone_toolchain.html#abi_compatibility:
+               # "We recommend using the -mthumb compiler flag to force the generation of 16-bit Thumb-2 instructions".
+               # With r13 of the ndk ruby 2.4.0 segfaults when built on arm with clang without -mthumb.
+               CFLAGS+=" -march=armv7-a -mfpu=neon -mfloat-abi=softfp -mthumb"

                LDFLAGS+=" -march=armv7-a -Wl,--fix-cortex-a8"
        elif [ "$TERMUX_ARCH" = "i686" ]; then
                # From $NDK/docs/CPU-ARCH-ABIS.html:
                LDFLAGS+=" -march=armv7-a -Wl,--fix-cortex-a8"
        elif [ "$TERMUX_ARCH" = "i686" ]; then
                # From $NDK/docs/CPU-ARCH-ABIS.html: