Update build instructions for OpenBSD

Author: nickg

README.md

@@ -57,15 +57,15 @@ the configure command. LLVM 7, 8, and 9 have all been tested.
 NVC also depends GNU Flex to generate the lexical analyser.
 
 [GtkWave](http://gtkwave.sourceforge.net/) can be used to view simulation
-waveforms. Version 3.3.79 or later is reqiured for the default FST format.
+waveforms. Version 3.3.79 or later is required for the default FST format.
 
 #### Debian and Ubuntu
 
 On a Debian derivative the following should be sufficient to install all
 required dependencies:
 
     sudo apt-get install build-essential automake autoconf autoconf-archive flex \
-        check llvm-dev pkg-config zlib1g-dev curl
+        check llvm-dev pkg-config zlib1g-dev
 
 #### Mac OS X
 
@@ -96,19 +96,19 @@ If you do not already have Cygwin it is easiest to build for MinGW using
 
 For Cygwin use `setup.exe` to install either `gcc` or `clang` and the following
 dependencies: `automake`, `autoconf`, `pkg-config`, `llvm`, `libllvm-devel`,
-`flex`, `libffi-devel`, `libcurses-devel`, `curl`, and `make`. Then follow the
+`flex`, `libffi-devel`, `libcurses-devel`, and `make`. Then follow the
 standard installation instructions above.
 
 #### OpenBSD
 
 Install the dependencies with `pkg_add`:
 
-    pkg_add -r automake-1.15p0 autoconf-2.69p2 libexecinfo llvm check libexecinfo
+    pkg_add automake autoconf libexecinfo llvm check libexecinfo
 
-Use a modern compiler such as Clang to build, as the system GCC does not support
-many modern language features.
+To configure using the system compiler:
 
-    ./configure --with-llvm=/usr/local/bin/llvm-config CC=clang CXX=clang++
+    ./configure LDFLAGS="-L/usr/local/lib" CC=/usr/bin/cc CXX=/usr/bin/c++ \
+        --with-llvm=/usr/local/bin/llvm-config
 
 Then follow the generic instructions above.
 

autogen.sh

@@ -1,8 +1,3 @@
 #!/bin/sh
-
-# Required for OpenBSD
-export AUTOCONF_VERSION=2.69
-export AUTOMAKE_VERSION=1.15
-
 cd $(git rev-parse --show-toplevel)
 autoreconf --force --install -I m4