Revert "fix conlict between PR 4515 and AIX shared obj support"

This reverts commit bdaa6705ca.

It turns out that PRs 4515 and 4520 break the tests under
lapack-netlib/TESTING which require SECOND and DSECND. IBM
has decided this is a bigger biger problem than the conflict
between lapack second_ and the xlf run time.

exports/Makefile

@@ -315,11 +315,6 @@ test : linktest.c
 
 linktest.c : $(GENSYM) ../Makefile.system ../getarch.c
 	./$(GENSYM) linktest  $(ARCH) "$(BU)" $(EXPRECISION) $(NO_CBLAS) $(NO_LAPACK) $(NO_LAPACKE) $(NEED2UNDERSCORES) $(ONLY_CBLAS) "$(SYMBOLPREFIX)" "$(SYMBOLSUFFIX)" $(BUILD_LAPACK_DEPRECATED) $(BUILD_BFLOAT16) $(BUILD_SINGLE) $(BUILD_DOUBLE) $(BUILD_COMPLEX) $(BUILD_COMPLEX16) > linktest.c
-ifeq ($(F_COMPILER), IBM)
-	mv linktest.c linktest.c.FIRST
-	egrep -v 'second_|dsecnd_' linktest.c.FIRST > linktest.c
-	rm linktest.c.FIRST
-endif
 
 clean ::
 	@rm -f *.def *.dylib __.SYMDEF* *.renamed