Properly check IS_CROSS_COMPILING variable

Two checks for IS_CROSS_COMPILING value in build-elf32.sh assumed that this
variable is "true" if set, which is wrong, because build-all.sh always sets
this variable, either to "yes" or "no". This patch fixes this problem, now
checks is done against "yes" value of this variable to figure out of this is
a cross-compilation of toolchain.

Signed-off-by: Anton Kolesov <[email protected]>

Author: anthony-kolesov

build-elf32.sh

@@ -186,7 +186,7 @@ fi
 # started to cause build issues. As a result it is required to disable them
 # explicitly - otherwise either there would a build failure or a bunch of
 # useless but large files.
-if [ $IS_CROSS_COMPILING ]; then
+if [ $IS_CROSS_COMPILING = yes ]; then
     pch_opt=--disable-libstdcxx-pch
 else
     pch_opt=
@@ -378,7 +378,7 @@ fi
 # Similar to ARC Linux targets, on Windows there are issues with exceptions when
 # GDB is compiled as a C++ applications, so as a temporary measure disable C++
 # when doing canadian cross.
-if [ $IS_CROSS_COMPILING ]; then
+if [ $IS_CROSS_COMPILING = yes ]; then
     cxx_build=--disable-build-with-cxx
 else
     cxx_build=