patchelf.cc: handle DT_MIPS_XHASH and .MIPS.xhash

glibc changed their ABI in commit
23c1c256ae7b0f010d0fcaff60682b620887b164 on 2019-Aug-29, by changing
the structure of the .gnu.hash data on MIPS and moving it to a
different section.  We need to adapt to this change by glibc.

Closes #368

Author: Adam Joseph

src/patchelf.cc

@@ -990,6 +990,10 @@ void ElfFile<ElfFileParamNames>::rewriteHeaders(Elf_Addr phdrAddress)
                 // some binaries might this section stripped
                 // in which case we just ignore the value.
                 if (shdr) dyn->d_un.d_ptr = (*shdr).get().sh_addr;
+	    } else if (d_tag == DT_MIPS_XHASH) {
+                // the .MIPS.xhash section was added to the glibc-ABI
+                // in commit 23c1c256ae7b0f010d0fcaff60682b620887b164
+                dyn->d_un.d_ptr = findSectionHeader(".MIPS.xhash").sh_addr;
             } else if (d_tag == DT_JMPREL) {
                 auto shdr = tryFindSectionHeader(".rel.plt");
                 if (!shdr) shdr = tryFindSectionHeader(".rela.plt");