RFR [XS] : jspawnhelper build settings cleanup

[Baesken, Matthias]

Hello all ,

Erik suggested to do further cleanups in  make/launcher/Launcher-java.base.gmk
 In the  jspawnhelper build section.

Those were the suggestions :


* Inline BUILD_JSPAWNHELPER_SRC, JSPAWNHELPER_CFLAGS,

BUILD_JSPAWNHELPER_DST_DIR and LINK_JSPAWNHELPER_OBJECTS. Since these

variables aren't conditionally changed anywhere, there is really no need

for the indirection.



* The whole business of "BUILD_JSPAWNHELPER_LDFLAGS +=

$(COMPILER_TARGET_BITS_FLAG)64" is confusing to me. Don't we trust the

compiler for a 64 bit target to produce a 64 bit binary given the

standard CFLAGS_JDKEXE and LDFLAGS_JDKLIB? I suspect this is just very

old and confused code



* The src dir only has the one src file, no need to explicitly list it

for include.



* The adding of childproc.o to LIBS can be accomplished using the

parameter EXTRA_OBJECT_FILES. By using that you automatically get the

dependency declaration so you can remove the line

"$(BUILD_JSPAWNHELPER): $(LINK_JSPAWNHELPER_OBJECTS)"



* The ifeq ($(BUILD_JSPAWNHELPER), 1) is also annoying, just move the

single conditional into it's place.


I prepared a webrev for  this.

After removing  the  BUILD_JSPAWNHELPER_LDFLAGS +=  $(COMPILER_TARGET_BITS_FLAG)64
I checked that  the  generated executable is still 64bit on AIX/Solaris/Mac-OSX  (however  the  -m64 seems to be gone on Mac after this change
Compared to before when generating the executable).


Btw the  BUILD_JEXEC  in    make/launcher/Launcher-java.base.gmk     looks also a bit strange (similar issues as the jspawnhelper section).


Bug :

https://bugs.openjdk.java.net/browse/JDK-8174086

  webrev  jdk10 :

http://cr.openjdk.java.net/~mbaesken/webrevs/8174086.0/

Please  review my change .

Thanks ,Matthias