is_asl handles per-file opt->o_unix.android_shlib

Also slide_sh_offset() handles so_slide.
TODO: if asl_delta, then relocate sh_offset that is above xct_off.
PT_DYNAMIC.p_offset and {.dynamic}.sh_offset must match; etc.

	modified:   p_lx_elf.cpp
	modified:   p_lx_elf.h
	modified:   p_unix.cpp

src/p_unix.cpp

@@ -56,9 +56,12 @@ PackUnix::PackUnix(InputFile *f) :
     COMPILE_TIME_ASSERT(sizeof(l_info) == 12)
     COMPILE_TIME_ASSERT(sizeof(p_info) == 12)
 
-    // Disable --android-shlib, file-by-file; undecided how to fix.
+    // opt->o_unix.android_shlib is global, but must be hint
+    // that applies only when an actual ET_DYN on EM_ARM or EM_ARM64.
+    // User might say "--android-shlib" but give mulitple files
+    // where some are ET_EXEC.
     saved_opt_android_shlib = opt->o_unix.android_shlib;
-    opt->o_unix.android_shlib = 0;
+    opt->o_unix.android_shlib = 0;  // Must apply selectively
 }
 
 PackUnix::~PackUnix()