pcre: separate variants of the library

- don't include the cxx variant in the default build,
  as it depends on libstdc++ (and it seems rarely used anyway)
- allow building pcre16 and pcre32 variants;
  pcre16 is the one needed by qt*, I think
- share the basic libs with all of the variants

pkgs/development/libraries/pcre/default.nix

@@ -1,9 +1,11 @@
-{ stdenv, fetchurl, unicodeSupport ? true, cplusplusSupport ? true
-, windows ? null
+{ stdenv, fetchurl
+, windows ? null, variant ? null, pcre
 }:
 
 with stdenv.lib;
 
+assert elem variant [ null "cpp" "pcre16" "pcre32" ];
+
 stdenv.mkDerivation rec {
   name = "pcre-8.37";
 
@@ -19,26 +21,28 @@ stdenv.mkDerivation rec {
 
   outputs = [ "dev" "out" "bin" "doc" "man" ];
 
-  configureFlags = ''
-    --enable-jit
-    ${if unicodeSupport then "--enable-unicode-properties" else ""}
-    ${if !cplusplusSupport then "--disable-cpp" else ""}
-  '';
+  configureFlags = [
+    "--enable-jit"
+    "--enable-unicode-properties"
+    "--disable-cpp"
+  ]
+    ++ optional (variant != null) "--enable-${variant}";
 
   doCheck = with stdenv; !(isCygwin || isFreeBSD);
     # XXX: test failure on Cygwin
     # we are running out of stack on both freeBSDs on Hydra
 
+  postFixup = ''
+    _moveToOutput bin/pcre-config "$dev"
+  ''
+    + optionalString (variant != null) ''
+    ln -sf -t "$out/lib/" '${pcre.out}'/lib/libpcre{,posix}.so.*.*.*
+  '';
+
   crossAttrs = optionalAttrs (stdenv.cross.libc == "msvcrt") {
     buildInputs = [ windows.mingw_w64_pthreads.crossDrv ];
   };
 
-  postInstall =
-    ''
-      mkdir $dev/bin
-      mv $bin/bin/pcre-config $dev/bin/
-    '';
-
   meta = {
     homepage = "http://www.pcre.org/";
     description = "A library for Perl Compatible Regular Expressions";

pkgs/top-level/all-packages.nix

@@ -7800,9 +7800,7 @@ let
     vtk = vtkWithQt4;
   };
 
-  pcre = callPackage ../development/libraries/pcre {
-    unicodeSupport = config.pcre.unicode or true;
-  };
+  pcre = callPackage ../development/libraries/pcre { };
 
   pdf2xml = callPackage ../development/libraries/pdf2xml {} ;
 
@@ -11545,9 +11543,7 @@ let
 
   inherit (gnome3) gitg;
 
-  giv = callPackage ../applications/graphics/giv {
-    pcre = pcre.override { unicodeSupport = true; };
-  };
+  giv = callPackage ../applications/graphics/giv { };
 
   gmrun = callPackage ../applications/misc/gmrun {};