ninja: pass separated paths to javac -sourcepath

The -sourcepath option can't be passed multiple times to javac, since it
simply overrides prior arguments. Instead -sourcepath takes a colon (or
semi-colon on windows) separated list of paths.

mesonbuild/backend/ninjabackend.py

@@ -1029,9 +1029,12 @@ int dummy;
         args += self.build.get_project_args(compiler, target.subproject)
         args += target.get_java_args()
         args += compiler.get_output_args(self.get_target_private_dir(target))
+        sourcepath = ''
         for i in target.include_dirs:
             for idir in i.get_incdirs():
-                args += ['-sourcepath', os.path.join(self.build_to_src, i.curdir, idir)]
+                sourcepath += os.path.join(self.build_to_src, i.curdir, idir) + os.pathsep
+        if sourcepath != '':
+            args += ['-sourcepath', sourcepath]
         rel_src = src.rel_to_builddir(self.build_to_src)
         plain_class_path = src.fname[:-4] + 'class'
         rel_obj = os.path.join(self.get_target_private_dir(target), plain_class_path)

test cases/java/5 includedirs/com/mesonbuild/Simple.java

@@ -0,0 +1,8 @@
+package com.mesonbuild;
+
+class Simple {
+    public static void main(String [] args) {
+        TextPrinter t = new TextPrinter("Printing from Java.");
+        t.print();
+    }
+}

test cases/java/5 includedirs/com/mesonbuild/TextPrinter.java

@@ -0,0 +1,14 @@
+package com.mesonbuild;
+
+class TextPrinter {
+
+    private String msg;
+    
+    TextPrinter(String s) {
+        msg = s;
+    }
+    
+    public void print() {
+        System.out.println(msg);
+    }
+}

test cases/java/5 includedirs/meson.build

@@ -0,0 +1,15 @@
+# The Ninja backend used to try and pass -sourcepath repeatedly for
+# multiple includes which would discard prior includes. Since this
+# won't compile without the '.' include, this ensures that multiple
+# paths are passed in a [semi-]colon separated list instead...
+
+project('includedirsjava', 'java')
+
+javaprog = jar('myprog',
+ 'com/mesonbuild/Simple.java',
+ 'com/mesonbuild/TextPrinter.java',
+  main_class : 'com.mesonbuild.Simple',
+  include_directories : [ include_directories('com'),
+                          include_directories('.'),
+                          include_directories('com/mesonbuild') ])
+test('subdirtest', javaprog)