Use suitable header rather than an extern declaration
Fix library categories

fix: "System and Control theory" -> "System and Control Theory"
fix: 'Commutative algebra' -> 'Commutative Algebra'
chg: also corresponding changes to emacs files (although they should better be generated in build time)
sync grammar.y
Merge branch 'spielwiese' of github.com:Singular/Sources into spielwiese
sync grammar.y
fix: tr. 599 (assign expr_list to def should yield an error)
chg: tests changed (fix tr.599, asssign expr_list to def)
test for tr.599
Merge branch 'spielwiese' of github.com:Singular/Sources into spielwiese
Merge branch 'spielwiese' of https://github.com/hannes14/Sources into spielwiese
a suggested change for gmp: if --with-gmp is set, also pass -R ... to
the linker as to NOT have to set the LD_LIBRARY_PATH
Idealy this should be handled using libtool I guess, as I don't know if
-R is always a valid linker flag.