gnu: java-openjfx-build: Add helpful patch.

* gnu/packages/java.scm (java-openjfx-build)[source]: Use it.
* gnu/packages/patches/java-openjfx-build-jdk_version.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.

Signed-off-by: Alexey Abramov <levenson@mmer.org>
Signed-off-by: Ludovic Courtès <ludo@gnu.org>

gnu/local.mk

@@ -1111,6 +1111,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/java-apache-ivy-port-to-latest-bouncycastle.patch	\
   %D%/packages/patches/java-commons-collections-fix-java8.patch \
   %D%/packages/patches/java-jeromq-fix-tests.patch		\
+  %D%/packages/patches/java-openjfx-build-jdk_version.patch     \
   %D%/packages/patches/java-powermock-fix-java-files.patch		\
   %D%/packages/patches/java-simple-xml-fix-tests.patch		\
   %D%/packages/patches/java-svg-salamander-Fix-non-det.patch	\

gnu/packages/java.scm

@@ -2499,7 +2499,8 @@ new Date();"))
                   #t))
               (sha256
                (base32
-                "0yg38mwpivswccv9n96k06x3iv82i4px1a9xg9l8dswzwmfj259f"))))
+                "0yg38mwpivswccv9n96k06x3iv82i4px1a9xg9l8dswzwmfj259f"))
+              (patches (search-patches "java-openjfx-build-jdk_version.patch"))))
     (build-system ant-build-system)
     (arguments
      `(#:jar-name "java-openjfx.jar"

gnu/packages/patches/java-openjfx-build-jdk_version.patch

@@ -0,0 +1,27 @@
+Subject: [PATCH] openjfx: Determine the version of Java in JDK_HOME
+
+Icedtea contains guix in its version, so build.gradle failes to run. Openjfx
+packaging is not trivial, so you will probably need to try build it with
+gradlew.
+
+---
+ build.gradle | 5 ++---
+ 1 file changed, 2 insertions(+), 3 deletions(-)
+
+diff --git a/build.gradle b/build.gradle
+index df82f63..2c626cd 100644
+--- a/build.gradle
++++ b/build.gradle
+@@ -742,9 +742,9 @@ try {
+     if (inStream.readLine() != null) {
+         String v = inStream.readLine();
+         if (v != null) {
+-            int ib = v.indexOf(" (build ");
++            int ib = v.indexOf(" (guix build ");
+             if (ib != -1) {
+-                String ver = v.substring(ib + 8, v.size() - 1);
++                String ver = v.substring(ib + 13, v.size() - 1);
+
+                 defineProperty("jdkRuntimeVersion", ver)
+                 defineProperty("jdkVersion", jdkRuntimeVersion.split("-")[0])
+2.24.1