minimal-bootstrap: trim gawk-static output

Disable optional gawk features not used by the bootstrap path and prune installed helper files, headers, libraries, documentation, locale data, and awk library scripts. The smoke test now covers a simple awk program, not only --version.

Size impact against upstream/staging:

- gawk-static closure: 6.001 MiB -> 1.549 MiB (-4.453 MiB)

Assisted-by: codex with gpt-5.5-high

pkgs/os-specific/linux/minimal-bootstrap/gawk/static.nix

@@ -48,6 +48,7 @@ bash.runCommand "${pname}-${version}"
       result:
       bash.runCommand "${pname}-get-version-${version}" { } ''
         ${result}/bin/awk --version
+        ${result}/bin/awk 'BEGIN { if (2 + 2 != 4) exit 1 }'
         mkdir $out
       '';
   }
@@ -62,6 +63,10 @@ bash.runCommand "${pname}-${version}"
       --build=${buildPlatform.config} \
       --host=${hostPlatform.config} \
       --disable-dependency-tracking \
+      --disable-extensions \
+      --disable-mpfr \
+      --disable-nls \
+      --disable-pma \
       CC=musl-gcc \
       CFLAGS=-static
 
@@ -71,4 +76,6 @@ bash.runCommand "${pname}-${version}"
     # Install
     make -j $NIX_BUILD_CORES install-strip
     rm $out/bin/gawkbug
+    rm -rf $out/etc $out/include $out/lib $out/libexec
+    rm -rf $out/share
   ''