patch 9.0.0088: pattern for detecting bitbake files is not sufficient

Problem:    Pattern for detecting bitbake files is not sufficient.
Solution:   Adjust the pattern. (Gregory Anders, closes #10743)

runtime/autoload/dist/ft.vim

@@ -519,7 +519,7 @@ export def FTinc()
     # headers so assume POV-Ray
     elseif lines =~ '^\s*\%({\|(\*\)' || lines =~? ft_pascal_keywords
       setf pascal
-    elseif lines =~# '\<\%(require\|inherit\)\>' || lines =~# '\w\+ = '
+    elseif lines =~# '\<\%(require\|inherit\)\>' || lines =~# '[A-Z][A-Za-z0-9_:${}]*\s\+\%(??\|[?:+]\)\?= '
       setf bitbake
     else
       FTasmsyntax()

src/testdir/test_filetype.vim

@@ -1864,6 +1864,31 @@ func Test_inc_file()
   call assert_equal('bitbake', &filetype)
   bwipe!
 
+  call writefile(['S = "${WORKDIR}"'], 'Xfile.inc')
+  split Xfile.inc
+  call assert_equal('bitbake', &filetype)
+  bwipe!
+
+  call writefile(['DEPENDS:append = " somedep"'], 'Xfile.inc')
+  split Xfile.inc
+  call assert_equal('bitbake', &filetype)
+  bwipe!
+
+  call writefile(['MACHINE ??= "qemu"'], 'Xfile.inc')
+  split Xfile.inc
+  call assert_equal('bitbake', &filetype)
+  bwipe!
+
+  call writefile(['PROVIDES := "test"'], 'Xfile.inc')
+  split Xfile.inc
+  call assert_equal('bitbake', &filetype)
+  bwipe!
+
+  call writefile(['RDEPENDS_${PN} += "bar"'], 'Xfile.inc')
+  split Xfile.inc
+  call assert_equal('bitbake', &filetype)
+  bwipe!
+
   " asm
   call writefile(['asmsyntax=foo'], 'Xfile.inc')
   split Xfile.inc

src/version.c

@@ -735,6 +735,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    88,
 /**/
     87,
 /**/