clang-analyzer: respect $NIX_CFLAGS_COMPILE

When using scan-build, you're often going to want to use it in the
context of a Nix expression with buildInputs, and the default wrapper
scripts will put things like include locations for those inputs
$NIX_CFLAGS_COMPILE. Thus, scan-build also needs to pass them to the
analyzer - while the link flags aren't relevant, the include flags are.

This is because the analyzer executable that gets run by scan-build is
*not* clang-wrapper, but the actual clang executable, so it doesn't
implicitly add such arguments. The build is two-stage - it runs the real
clang wrapper once, and then the analyzer once.

Signed-off-by: Austin Seipp <aseipp@pobox.com>

pkgs/development/tools/analysis/clang-analyzer/0001-Fix-scan-build-to-use-NIX_CFLAGS_COMPILE.patch

@@ -0,0 +1,33 @@
+From 6ab08bc1c889e4fb9a39432b1a654eaa19ee65eb Mon Sep 17 00:00:00 2001
+From: Austin Seipp <aseipp@pobox.com>
+Date: Fri, 2 May 2014 12:28:23 -0500
+Subject: [PATCH] Fix scan-build to use NIX_CFLAGS_COMPILE
+
+Signed-off-by: Austin Seipp <aseipp@pobox.com>
+---
+ tools/scan-build/ccc-analyzer | 9 +++++++++
+ 1 file changed, 9 insertions(+)
+
+diff --git a/tools/scan-build/ccc-analyzer b/tools/scan-build/ccc-analyzer
+index b463ec0..9d39dd0 100755
+--- a/tools/scan-build/ccc-analyzer
++++ b/tools/scan-build/ccc-analyzer
+@@ -207,6 +207,15 @@ sub Analyze {
+       push @Args, "-Xclang", "-analyzer-viz-egraph-ubigraph";
+     }
+ 
++
++    # Add Nix flags to analysis
++    if (defined $ENV{'NIX_CFLAGS_COMPILE'}) {
++      my @nixArgs = split(/\s+/, $ENV{'NIX_CFLAGS_COMPILE'});
++      foreach my $nixArg (@nixArgs) {
++        push @Args, $nixArg;
++      }
++    }
++
+     my $AnalysisArgs = GetCCArgs("--analyze", \@Args);
+     @CmdArgs = @$AnalysisArgs;
+   }
+-- 
+1.8.3.2
+

pkgs/development/tools/analysis/clang-analyzer/default.nix

@@ -9,6 +9,7 @@ stdenv.mkDerivation rec {
     sha256 = "06rb4j1ifbznl3gfhl98s7ilj0ns01p7y7zap4p7ynmqnc6pia92";
   };
 
+  patches = [ ./0001-Fix-scan-build-to-use-NIX_CFLAGS_COMPILE.patch ];
   buildInputs = [ clang llvmPackages.clang perl makeWrapper ];
   buildPhase = "true";
 
@@ -18,7 +19,10 @@ stdenv.mkDerivation rec {
     cp -R tools/scan-build $out/libexec
 
     makeWrapper $out/libexec/scan-view/scan-view $out/bin/scan-view
-    makeWrapper $out/libexec/scan-build/scan-build $out/bin/scan-build --add-flags "--use-cc=${clang}/bin/clang" --add-flags "--use-c++=${clang}/bin/clang++" --add-flags "--use-analyzer=${llvmPackages.clang}/bin/clang"
+    makeWrapper $out/libexec/scan-build/scan-build $out/bin/scan-build \
+      --add-flags "--use-cc=${clang}/bin/clang" \
+      --add-flags "--use-c++=${clang}/bin/clang++" \
+      --add-flags "--use-analyzer='${llvmPackages.clang}/bin/clang'"
   '';
 
   meta = {