Organize pages into directories and shorter file names.  Use lower-case
names for directories and capitalized names for files.  This produces a
pleasing sort order in the GitLab Wiki navigation page.

Also rename entry page `CMake.md` to `Home.md` to match GitLab Wiki
conventions.

doc/cmake/platform_dependent_issues/IA64-FPIC-problem.md

+bar.c:
+
+    int i = 0;
+    void bar()
+     {
+     i = 5;
+     }
+
+foo.c:
+
+    extern void bar();
+    void foo()
+      {
+      bar();
+      }
+
+Compiled with
+
+    rm -f libbar.a *.o
+    gcc -c bar.c
+    ar cr libbar.a bar.o
+    gcc -c foo.c
+    gcc -shared -o libfoo.so foo.o -L. -lbar
+
+Will
+    fail:
+
+    /usr/bin/ld: bar.o: @gprel relocation against dynamic symbol i collect2: ld returned 1 exit status
+
+But, putting:
+
+    gcc -fPIC -c bar.c
+
+works.
+
+----
+This page was initially populated by conversion from its [original location](https://public.kitware.com/Wiki/CMake_IA64_FPIC_problem) in another wiki.