gnu: hmmer: Build reproducibly.

* gnu/packages/patches/hmmer-remove-cpu-specificity.patch: New file.
* gnu/packages/bioinformatics.scm (hmmer): Use it.

gnu/packages/patches/hmmer-remove-cpu-specificity.patch

@@ -0,0 +1,22 @@
+This patch removes compilation flags which make the build for the machine
+where compilation takes place, rendering the build not reproducible.
+
+diff --git a/configure b/configure
+index 8b6aaef..49a6afc 100755
+--- a/configure
++++ b/configure
+@@ -6125,14 +6125,6 @@ fi # guess arch
+ 
+ if test "x$ax_gcc_arch" != x -a "x$ax_gcc_arch" != xno; then
+ for arch in $ax_gcc_arch; do
+-  if test "x$acx_maxopt_portable" = xyes; then # if we require portable code
+-    flags="-mtune=$arch"
+-    # -mcpu=$arch and m$arch generate nonportable code on every arch except
+-    # x86.  And some other arches (e.g. Alpha) don't accept -mtune.  Grrr.
+-    case $host_cpu in i*86|x86_64*) flags="$flags -mcpu=$arch -m$arch";; esac
+-  else
+-    flags="-march=$arch -mcpu=$arch -m$arch"
+-  fi
+   for flag in $flags; do
+     as_CACHEVAR=`$as_echo "ax_cv_check_cflags__$flag" | $as_tr_sh`
+ { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether C compiler accepts $flag" >&5