bash: Remove .build files for reproducible builds

Bash has an internal "build number" that it tracks and automatically
increments ever time a given builds is made from the same sandbox.
However, this can make builds non-reproducible in the event that a build
directory is reused multiple times.

Remove the .build files after every build if reproducible builds have
been requested which will reset the build build number for the next
build.

(From OE-Core rev: 9754be5c22de877bd53226908d03d2eef5751808)

Signed-off-by: Joshua Watt <JPEWhacker@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-extended/bash/bash.inc

@@ -39,6 +39,12 @@ RDEPENDS_${PN}-ptest_append_libc-glibc = " \
 
 CACHED_CONFIGUREVARS += "headersdir=${includedir}/${PN}"
 
+do_compile_prepend() {
+    # Remove any leftover .build files. This ensures that bash always has the
+    # same version number and keeps builds reproducible
+    rm -f ${B}/.build
+}
+
 do_compile_ptest () {
 	oe_runmake buildtest
 }