The make javac rule uses [ -s srcjar-list ] to decide whether or
not to run javac. zipsync was putting a trailing "\n" in the
list file, so the file was never empty. There was one case of a
package that contained no source files (so java-source-list was
empty) and had a res directory with an xml file that declared no
resources (so aapt.jar was created but empty). The 1-byte
srcjar-list file caused javac to run and error with:
javac: no source files
Test: m checkbuild
Change-Id: I26b394b66bf81e4f5abbd27e4dc06bee1d9420a8
extract_srcjars.sh uses zipinfo and unzip, which fail with an
error on an empty zip file. Instead of trying to hack around
this (which is hard to make guarantees for since they are
non-hermetic host tools), replace them with a go tool to unzip
a set of zip files into a directory.
Bug: 73885582
Test: m checkbuild
Change-Id: I151fed347ed5196726e36866ffc27bc831799afb
