Strip leading source tree dir name from install files if it exists.

mesonbuild/backend/ninjabackend.py

@@ -547,12 +547,13 @@ int dummy;
             assert(isinstance(de, build.Data))
             subdir = de.install_dir
             for f in de.sources:
+                plain_f = os.path.split(f)[1]
                 if de.in_sourcetree:
                     srcprefix = self.environment.get_source_dir()
                 else:
                     srcprefix = self.environment.get_build_dir()
                 srcabs = os.path.join(srcprefix, de.source_subdir, f)
-                dstabs = os.path.join(subdir, f)
+                dstabs = os.path.join(subdir, plain_f)
                 i = [srcabs, dstabs]
                 d.data.append(i)
 

test cases/common/12 data/installed_files.txt

@@ -1,3 +1,4 @@
 usr/share/progname/datafile.dat
 usr/share/progname/vanishing.dat
+usr/share/progname/vanishing2.dat
 etc/etcfile.dat

test cases/common/12 data/meson.build

@@ -1,4 +1,7 @@
 project('data install test', 'c')
 install_data(sources : 'datafile.dat', install_dir : 'share/progname')
 install_data(sources : 'etcfile.dat', install_dir : '/etc')
+
 subdir('vanishing')
+
+install_data(sources : 'vanishing/vanishing2.dat', install_dir : 'share/progname')

test cases/common/12 data/vanishing/vanishing2.dat

@@ -0,0 +1,4 @@
+This is a data file to be installed in a subdirectory.
+
+It is installed from a different subdir to test that the
+installer strips the source tree dir prefix.