diff -up Waterfox-ff4597172229f8d71940c3885b74b903b7b1821a/security/sandbox/linux/moz.build.1516803 Waterfox-ff4597172229f8d71940c3885b74b903b7b1821a/security/sandbox/linux/moz.build
--- Waterfox-ff4597172229f8d71940c3885b74b903b7b1821a/security/sandbox/linux/moz.build.1516803	2019-01-08 11:39:44.002864753 -0200
+++ Waterfox-ff4597172229f8d71940c3885b74b903b7b1821a/security/sandbox/linux/moz.build	2019-01-08 11:40:38.624513603 -0200
@@ -98,8 +98,8 @@ if CONFIG['GNU_CXX']:
 # gcc lto likes to put the top level asm in syscall.cc in a different partition
 # from the function using it which breaks the build.  Work around that by
 # forcing there to be only one partition.
-if '-flto' in CONFIG['OS_CXXFLAGS'] and not CONFIG['CLANG_CXX']:
-    LDFLAGS += ['--param lto-partitions=1']
+if CONFIG['CC_TYPE'] != 'clang':
+    LDFLAGS += ['--param', 'lto-partitions=1']
 
 DEFINES['NS_NO_XPCOM'] = True
 DisableStlWrapping()