waf: make executable runnable (#388010)

doc/hooks/waf.section.md

@@ -14,7 +14,7 @@ The variables below are exclusive of `wafHook`.
 
 Location of the `waf` tool. It defaults to `./waf`, to honor software projects that include it directly inside their source trees.
 
-If `wafPath` doesn't exist, then `wafHook` will copy the `waf` provided from Nixpkgs to it.
+If the file pointed by `wafPath` doesn't exist, then `waf` provided by Nixpkgs will be used.
 
 #### `wafFlags` {#waf-flags}
 

pkgs/by-name/wa/waf/package.nix

@@ -4,6 +4,7 @@
 , callPackage
 , ensureNewerSourcesForZipFilesHook
 , python3
+, makeWrapper
 # optional list of extra waf tools, e.g. `[ "doxygen" "pytest" ]`
 , extraTools ? []
 }:
@@ -22,6 +23,7 @@ stdenv.mkDerivation (finalAttrs: {
   nativeBuildInputs = [
     ensureNewerSourcesForZipFilesHook
     python3
+    makeWrapper
   ];
 
   buildInputs = [
@@ -49,14 +51,20 @@ stdenv.mkDerivation (finalAttrs: {
 
     python waf-light build ${extraToolsList}
 
+    substituteInPlace waf \
+      --replace "w = test(i + '/lib/' + dirname)" \
+                "w = test('$out/${python3.sitePackages}')"
+
     runHook postBuild
   '';
 
   installPhase = ''
     runHook preInstall
 
-    install -D waf $out/bin/waf
-
+    install -D waf "$out"/bin/waf
+    wrapProgram "$out"/bin/waf --set PYTHONPATH "$out"/${python3.sitePackages}
+    mkdir -p "$out"/${python3.sitePackages}/
+    cp -r waflib "$out"/${python3.sitePackages}/
     runHook postInstall
   '';
 

pkgs/by-name/wa/waf/setup-hook.sh

@@ -4,8 +4,7 @@ wafConfigurePhase() {
     runHook preConfigure
 
     if ! [ -f "${wafPath:=./waf}" ]; then
-        echo "copying waf to $wafPath..."
-        cp @waf@/bin/waf "$wafPath"
+        wafPath="@waf@/bin/waf"
     fi
 
     if [ -z "${dontAddPrefix:-}" ] && [ -n "$prefix" ]; then