The parallel builds aborts because parallel execution of flex breaks
due to the usage of the same temporary file names. This stems from
using a hard coded temp file name "~flex_temp_out_main" and
"random numbers" based on constants in mkstempFILE.
Fixing those issues by embedding the current PID into the temp file
names. Patch is in gnuwin32/patches/win_flex.patch
Change-Id: I6c0cd499b3c9c35128280ec0fee5e450a9ca097f
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
