replace remaining bash-only features in the update script

We used to need more features, but as the Makefile.am's
stopped being dynamically generated, there is less need.

README.md

@@ -62,7 +62,7 @@ If you have checked this source using Git, follow these initial steps to
 prepare the source tree for building:
 
 1. Ensure you have the following packages installed:
-   automake, autoconf, bash, git, libtool, perl, pod2man
+   automake, autoconf, git, libtool, perl, pod2man
 2. Run './autogen.sh' to prepare the source tree for building or
    run './dist.sh' to prepare a tarball.
 

update.sh

@@ -1,4 +1,4 @@
-#!/usr/bin/env bash
+#!/bin/sh
 set -e
 
 openbsd_branch=`cat OPENBSD_BRANCH`
@@ -28,17 +28,17 @@ libtls_src=$CWD/openbsd/src/lib/libtls
 openssl_app_src=$CWD/openbsd/src/usr.bin/openssl
 
 # load library versions
-source $libcrypto_src/crypto/shlib_version
+. $libcrypto_src/crypto/shlib_version
 libcrypto_version=$major:$minor:0
 echo "libcrypto version $libcrypto_version"
 echo $libcrypto_version > crypto/VERSION
 
-source $libssl_src/ssl/shlib_version
+. $libssl_src/ssl/shlib_version
 libssl_version=$major:$minor:0
 echo "libssl version $libssl_version"
 echo $libssl_version > ssl/VERSION
 
-source $libtls_src/shlib_version
+. $libtls_src/shlib_version
 libtls_version=$major:$minor:0
 echo "libtls version $libtls_version"
 echo $libtls_version > tls/VERSION
@@ -143,7 +143,7 @@ $CP crypto/compat/ui_openssl_win.c crypto/ui
 asm_src=$libssl_src/src/crypto
 gen_asm_stdout() {
 	perl $asm_src/$2 $1 > $3.tmp
-	[[ $1 == "elf" ]] && cat <<-EOF >> $3.tmp
+	[ $1 = "elf" ] && cat <<-EOF >> $3.tmp
 	#if defined(HAVE_GNU_STACK)
 	.section .note.GNU-stack,"",%progbits
 	#endif
@@ -152,7 +152,7 @@ gen_asm_stdout() {
 }
 gen_asm() {
 	perl $asm_src/$2 $1 $3.tmp
-	[[ $1 == "elf" ]] && cat <<-EOF >> $3.tmp
+	[ $1 = "elf" ] && cat <<-EOF >> $3.tmp
 	#if defined(HAVE_GNU_STACK)
 	.section .note.GNU-stack,"",%progbits
 	#endif