Let libgap build a shared library on Cygwin

[jpflori]

We need to pass -no-undefined to libtool, the proper place is in libgap_la_LDFLAGS, potentially only on Cygwin and other Windows systems (have a look in GMP/MPIR/MPFR for examples), but should not hurt anyway elsewhere if added unconditionally.

(By the way the spkg-install script is terrible, does not use $MAKE, use [ ] and [[ ]], sets CXXFLAGS but does not export it...)

http://www.stp.dias.ie/~vbraun/Sage/spkg/libgap-4.5.7.p1.spkg

CC: @kcrisman @dimpase @vbraun

Component: packages: standard

Keywords: cygwin spkg libgap

Author: Volker Braun, Jean-Pierre Flori

Reviewer: Jean-Pierre Flori, Dmitrii Pasechnik

Merged: sage-5.8.beta0

Issue created by migration from https://trac.sagemath.org/ticket/14038

[jpflori]

comment:1

And now MPIR defines __GNU_MP_RELEASE so the __GMP_MP_RELEASE hack is not needed anymore here or in gap spkg.

[vbraun]

comment:2

I made #14039 to keep track of what to change for the next GAP update.

[vbraun]

comment:3

I've made a new spkg that includes the --no-undefined. Please let me know if it fixes things.

[vbraun]

Description changed:

--- 
+++ 
@@ -1,3 +1,6 @@
 We need to pass -no-undefined to libtool, the proper place is in libgap_la_LDFLAGS, potentially  only on Cygwin and other Windows systems (have a look in GMP/MPIR/MPFR for examples), but should not hurt anyway elsewhere if added unconditionally.
 
 (By the way the spkg-install script is terrible, does not use $MAKE, use [ ] and [[ ]], sets CXXFLAGS but does not export it...)
+
+
+http://www.stp.dias.ie/~vbraun/Sage/spkg/libgap-4.5.7.p1.spkg

[vbraun]

Author: Volker Braun

[jpflori]

comment:4

I've had a quick look at the spkg and it seems fine except there should be only one dash in front of no-undefined (not sure though putting two will break things).

The spkg-install cript looks cleaner.
Would you mind replacing the last double brackets by simple ones?
The use of double brackets does not seem necerssary for the simple tests involved.

A line for the version bump in SPKG.txt would be nice as well.

It should fix things on Cygwin (I crafted my own spkg yesterday and everything went fine, see CygwinPort).
The question should then rather be: Does it break things on other systems? (it should not.)

[jpflori]

Reviewer: Jean-Pierre Flori