[Bug ada/81104] New: gnattools: LDFLAGS=-Wl,--as-needed has no effect after the libraries

[nicolas.boulenguez at free dot fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81104

            Bug ID: 81104
           Summary: gnattools: LDFLAGS=-Wl,--as-needed has no effect after
                    the libraries
           Product: gcc
           Version: 7.0.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: ada
          Assignee: unassigned at gcc dot gnu.org
          Reporter: nicolas.boulenguez at free dot fr
  Target Milestone: ---

Created attachment 41556
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=41556&action=edit
Short and tested but ugly workaround

Gnatlink moves GCC_LINK linker options after other options, probably so that
standard libraries come after user libraries in case --as-needed is activated.
However, if --as-needed is activated via LDFLAGS, it is appended via GCC_LINK
and comes too late on the eventual command line.
All GCC_LINKS expansions but one are followed by an expansion of TOOLS_LIBS, so
TOOLS_LIBS seems to be the right place for LDFLAGS.

The attached patch attempts not to be intrusive, but I suggest replacing each
$(TOOLS_LIBS) with $(LDFLAGS) $(TOOLS_LIBS) for a more logic and readable
solution.