toolchain/gcc: eliminate uClibc atexit hack

This seems to be over 10 years old. It doesn't seem to be needed anymore.

Tested on malta with uClibc (selected BROKEN).

Signed-off-by: Rosen Penev <rosenp@gmail.com>

toolchain/gcc/common.mk

@@ -115,7 +115,8 @@ GCC_CONFIGURE:= \
 		--with-mpfr=$(TOPDIR)/staging_dir/host \
 		--with-mpc=$(TOPDIR)/staging_dir/host \
 		--disable-decimal-float \
-		--with-diagnostics-color=auto-if-env
+		--with-diagnostics-color=auto-if-env \
+		--enable-__cxa_atexit
 ifneq ($(CONFIG_mips)$(CONFIG_mipsel),)
   GCC_CONFIGURE += --with-mips-plt
 endif
@@ -150,14 +151,6 @@ ifdef CONFIG_sparc
 		--with-long-double-128
 endif
 
-ifeq ($(LIBC),uClibc)
-  GCC_CONFIGURE+= \
-		--disable-__cxa_atexit
-else
-  GCC_CONFIGURE+= \
-		--enable-__cxa_atexit
-endif
-
 ifneq ($(GCC_ARCH),)
   GCC_CONFIGURE+= --with-arch=$(GCC_ARCH)
 endif