configure: Disable GCC checking on BE builds

GCC currently does not support the RISC-V Vector Extension
on big-endian builds, which causes the stage1 self-tests to fail.
Disabling them is a temporary fix, until we get RVV working on
big-endian systems.

Author: aleksapaunovic-htec

configure

@@ -4185,16 +4185,18 @@ else $as_nop
 fi
 
 # Check whether --enable-gcc-checking was given.
-if test ${enable_gcc_checking+y}
+if test ${enable_gcc_checking+y} && test "x$endian" = xlittle
 then :
   enableval=$enable_gcc_checking;
 fi
 
-
-if test "x$enable_gcc_checking" = xyes
+# FIXME: Stage1 self-tests fail on BE builds due to lack of RVV support. Disable them for now.
+if test "x$enable_gcc_checking" = xyes && "x$endian" = xlittle
 then :
   gcc_checking=--enable-checking
-
+elif test "x$endian" = xbig
+then :
+  gcc_checking="--enable-checking=no --disable-stage1-checking"
 else $as_nop
   gcc_checking=""