Use PKG_INSTALL and PKG_BUILD_PARALLEL for consistency.

Rebase patch.

Signed-off-by: Rosen Penev <rosenp@gmail.com>

Based on debian patch. LDFLAGS were not being passed, which caused relro
to not be applies.

Also made stock CFLAGS optional. -fkeep-inline was keeping sizes high.

Removed PKG_NO_MIPS16 as the original problem seems to be gone.

Size from 54338 to 50761

Signed-off-by: Rosen Penev <rosenp@gmail.com>