GH429: Add clang to travis

Signed-off-by: NRich Salz <rsalz@akamai.com>
Reviewed-by: NAndy Polyakov <appro@openssl.org>

.travis.yml

 language: c
 
 addons:
-    apt_packages:
-        - binutils-mingw-w64
-        - gcc-mingw-w64
+    apt:
+        packages:
+            - gcc-5
+            - binutils-mingw-w64
+            - gcc-mingw-w64
+        sources:
+            - ubuntu-toolchain-r-test
 
 os:
     - linux
@@ -12,6 +16,7 @@ os:
 compiler:
     - clang
     - gcc
+    - gcc-5
     - i686-w64-mingw32-gcc
     - x86_64-w64-mingw32-gcc
 
@@ -21,7 +26,13 @@ env:
     - CONFIG_OPTS="--debug --strict-warnings"
 
 matrix:
+    include:
+        - os: linux
+          compiler: gcc-5
+          env: CONFIG_OPTS="--debug --strict-warnings -fsanitize=address"
     exclude:
+        - os: osx
+          compiler: gcc-5
         - os: osx
           compiler: i686-w64-mingw32-gcc
         - os: osx

Configure

@@ -1640,7 +1640,7 @@ if ($strict_warnings)
 	my $ecc = $cc;
 	$ecc = "clang" if `$cc --version 2>&1` =~ /clang/;
 	my $wopt;
-	die "ERROR --strict-warnings requires gcc or clang" unless ($ecc =~ /gcc$/ or $ecc =~ /clang$/);
+	die "ERROR --strict-warnings requires gcc or clang" unless ($ecc =~ /gcc(-\d(\.\d)*)?$/ or $ecc =~ /clang$/);
 	foreach $wopt (split /\s+/, $gcc_devteam_warn)
 		{
 		$cflags .= " $wopt" unless ($cflags =~ /$wopt/)