math/py-z3-solver: fix build on powerpc

ld: error: can't create dynamic relocation R_PPC_ADDR16_LO against local symbol in readonly segment; recompile object files with -fPIC or pass '-Wl,-z,notext' to allow text relocations in the output

math/py-z3-solver/Makefile

@@ -10,6 +10,8 @@ COMMENT=	Python binding for Z3 Theorem Prover
 LICENSE=	MIT
 LICENSE_FILE=	${WRKSRC}/../../../LICENSE.txt
 
+CFLAGS_powerpc=	-fPIC
+
 BROKEN_i386=	can't create dynamic relocation R_386_32 against symbol: .L.str in readonly segment; see https://github.com/Z3Prover/z3/issues/2442
 
 # CAVEAT: There should have LIB_DEPENDS=libz3.so:math/z3, but currently it rebuilds all code, see https://github.com/Z3Prover/z3/issues/1767