Fix multilib conflicts in js-config.h

The multilib header handling is copied verbatim from libjpeg-turbo.

mozjs60.spec

@@ -16,7 +16,7 @@
 
 Name:           mozjs%{major}
 Version:        60.9.0
-Release:        2%{?dist}
+Release:        3%{?dist}
 Summary:        SpiderMonkey JavaScript library
 
 License:        MPLv2.0 and MPLv1.1 and BSD and GPLv2+ and GPLv3+ and LGPLv2+ and AFL and ASL 2.0
@@ -160,6 +160,43 @@ popd
 # Fix permissions
 chmod -x %{buildroot}%{_libdir}/pkgconfig/*.pc
 
+# Avoid multilib conflicts
+case `uname -i` in
+  i386 | ppc | s390 | sparc )
+    wordsize="32"
+    ;;
+  x86_64 | ppc64 | s390x | sparc64 )
+    wordsize="64"
+    ;;
+  *)
+    wordsize=""
+    ;;
+esac
+
+if test -n "$wordsize"
+then
+  mv %{buildroot}%{_includedir}/mozjs-60/js-config.h \
+     %{buildroot}%{_includedir}/mozjs-60/js-config-$wordsize.h
+
+  cat >%{buildroot}%{_includedir}/mozjs-60/js-config.h <<EOF
+#ifndef JS_CONFIG_H_MULTILIB
+#define JS_CONFIG_H_MULTILIB
+
+#include <bits/wordsize.h>
+
+#if __WORDSIZE == 32
+# include "js-config-32.h"
+#elif __WORDSIZE == 64
+# include "js-config-64.h"
+#else
+# error "unexpected value for __WORDSIZE macro"
+#endif
+
+#endif
+EOF
+
+fi
+
 # Remove unneeded files
 rm %{buildroot}%{_bindir}/js%{major}-config
 rm %{buildroot}%{_libdir}/libjs_static.ajs
@@ -200,6 +237,9 @@ ln -s libmozjs-%{major}.so.0 %{buildroot}%{_libdir}/libmozjs-%{major}.so
 %{_includedir}/mozjs-%{major}/
 
 %changelog
+* Tue Sep 10 2019 Kalev Lember <klember@redhat.com> - 60.9.0-3
+- Fix multilib conflicts in js-config.h
+
 * Sat Sep 07 2019 Kalev Lember <klember@redhat.com> - 60.9.0-2
 - Backport patches for s390x support