Normalize full paths in implicit link library list

Teach CMakeParseImplicitLinkInfo to convert implicit link library full
paths to a canonical form.  This makes them more reproducible in case
different language compiler front-ends add the same library by different
paths e.g. ".../libA.a" and "...//libA.a".

Add a case to the CMake.ImplicitLinkInfo test to cover removal of extra
slashes from both library and directory paths.

Modules/CMakeParseImplicitLinkInfo.cmake

@@ -103,6 +103,12 @@ function(CMAKE_PARSE_IMPLICIT_LINK_INFO text lib_var dir_var log_var obj_regex)
   foreach(lib IN LISTS implicit_libs_tmp)
     if("${lib}" MATCHES "^(crt.*\\.o|gcc.*|System.*)$")
       set(log "${log}  remove lib [${lib}]\n")
+    elseif(IS_ABSOLUTE "${lib}")
+      get_filename_component(abs "${lib}" ABSOLUTE)
+      if(NOT "x${lib}" STREQUAL "x${abs}")
+        set(log "${log}  collapse lib [${lib}] ==> [${abs}]\n")
+      endif()
+      list(APPEND implicit_libs "${abs}")
     else()
       list(APPEND implicit_libs "${lib}")
     endif()

Tests/CMakeTests/ImplicitLinkInfoTest.cmake.in

@@ -99,6 +99,12 @@ set(linux64_test1_libs "${linux64_gcc_libs}")
 set(linux64_test1_dirs "${linux64_gcc_dirs}")
 list(APPEND platforms linux64_test1)
 
+# sunCC dummy.cxx -v # extra slashes
+set(linux64_test2_text "/usr/bin/ld --eh-frame-hdr -m elf_x86_64 -dynamic-linker /lib64/ld-linux-x86-64.so.2 /opt/sun/sunstudio12/prod/lib/amd64//crti.o /opt/sun/sunstudio12/prod/lib/amd64/crt1x.o /opt/sun/sunstudio12/prod/lib/amd64/values-xa.o dummy.o -Y \"/opt/sun/sunstudio12/prod/lib//amd64:/lib64:/usr//lib64\" -Qy -lc /opt/sun/sunstudio12/prod/lib/amd64//libc_supp.a /opt/sun/sunstudio12/prod/lib/amd64/crtn.o")
+set(linux64_test2_libs "c;/opt/sun/sunstudio12/prod/lib/amd64/libc_supp.a")
+set(linux64_test2_dirs "/opt/sun/sunstudio12/prod/lib/amd64;/lib64;/usr/lib64")
+list(APPEND platforms linux64_test2)
+
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 # Mac