[Ada] QNX shared libraries - arm-qnx build gnatlib .so's

[Pierre-Marie de Rodat via Gcc-patches]

Shared libraries now fully supported on arm-qnx.

Tested on x86_64-pc-linux-gnu, committed on trunk

gcc/ada/

        * Makefile.rtl (GNATLIB_SHARED): Revert disablement for arm-qnx.
diff --git a/gcc/ada/Makefile.rtl b/gcc/ada/Makefile.rtl
--- a/gcc/ada/Makefile.rtl
+++ b/gcc/ada/Makefile.rtl
@@ -1542,9 +1542,8 @@ ifeq ($(strip $(filter-out arm aarch64 %qnx,$(target_cpu) $(target_os))),)
        s-dorepr.adb<libgnat/s-dorepr__fma.adb
      LIBGNAT_TARGET_PAIRS += $(GNATRTL_128BIT_PAIRS)
      EXTRA_GNATRTL_NONTASKING_OBJS = $(GNATRTL_128BIT_OBJS)
-     # Temporarily restrict shared library build to aarch64 (V303-025)
-     GNATLIB_SHARED = gnatlib-shared-dual
   endif
+  GNATLIB_SHARED = gnatlib-shared-dual
   EXTRA_LIBGNAT_OBJS+=$(SIGTRAMP_OBJ)
   EXTRA_LIBGNAT_SRCS+=sigtramp.h