Disable getentropy on Mac to support 10.10

According to the headers, getentropy became available in MacOSX 10.12

We still have some builders on Mac 10.10 that are downstream consumers
of this python executable. I don't expect them to live for that much
longer, but in the meantime, disable the getentropy call that's causing
them problems.

Bug: 180443630
Test: run built py3-cmd binary on a 10.10 machine
Change-Id: I0145301d12e497df08bb94a1ffa679efa2d8e6fd
diff --git a/android/regen.sh b/android/regen.sh
index 0145ff1..1c0e235 100755
--- a/android/regen.sh
+++ b/android/regen.sh
@@ -39,6 +39,8 @@
 ../../../configure
 
 if [ $DIR == "darwin_x86_64" ]; then
+  # getentropy is not safe on <10.12, which we still target
+  sed -ibak "s%#define HAVE_GETENTROPY 1%/* #undef HAVE_GETENTROPY */%" pyconfig.h
   # utimensat and futimens are not safe on <10.13, which we still target
   sed -ibak "s%#define HAVE_UTIMENSAT 1%/* #undef HAVE_UTIMENSAT */%" pyconfig.h
   sed -ibak "s%#define HAVE_FUTIMENS 1%/* #undef HAVE_FUTIMENS */%" pyconfig.h