texinfoInteractive: fix cross build

pkgs/development/tools/misc/texinfo/common.nix

@@ -6,6 +6,10 @@
 , interactive ? false, ncurses, procps
 }:
 
+let
+  crossBuildTools = interactive && stdenv.hostPlatform != stdenv.buildPlatform;
+in
+
 with stdenv.lib;
 
 stdenv.mkDerivation {
@@ -17,7 +21,13 @@ stdenv.mkDerivation {
     inherit sha256;
   };
 
-  patches = optional (version == "6.5") ./perl.patch;
+  patches = optional (version == "6.5") ./perl.patch
+    ++ optional crossBuildTools ./cross-tools-flags.patch;
+
+  # ncurses is required to build `makedoc'
+  # this feature is introduced by the ./cross-tools-flags.patch
+  NATIVE_TOOLS_CFLAGS = if crossBuildTools then "-I${getDev buildPackages.ncurses}/include" else null;
+  NATIVE_TOOLS_LDFLAGS = if crossBuildTools then "-L${getLib buildPackages.ncurses}/lib" else null;
 
   # We need a native compiler to build perl XS extensions
   # when cross-compiling.

pkgs/development/tools/misc/texinfo/cross-tools-flags.patch

@@ -0,0 +1,12 @@
+diff -ur texinfo-6.5/configure texinfo-6.5-patched/configure
+--- texinfo-6.5/configure	2017-09-13 03:50:18.000000000 +0900
++++ texinfo-6.5-patched/configure	2019-12-28 17:39:06.692818866 +0900
+@@ -23281,7 +23281,7 @@
+   # env -i gives this build host configure a clean environment;
+   # consequently, we have to re-initialize $PATH.
+   env -i CC="$BUILD_CC" AR="$BUILD_AR" RANLIB="$BUILD_RANLIB" \
+-      PATH="$PATH" \
++      PATH="$PATH" CFLAGS="$NATIVE_TOOLS_CFLAGS" LDFLAGS="$NATIVE_TOOLS_LDFLAGS" \
+       tools_only=1 \
+     ${confdir}/configure --build=${build} --host=${build} \
+                          --disable-rpath --disable-nls