Merge pull request #1 from IBM/readme_edit

Update README.md

Author: smcmahonibm

README.md

@@ -2,25 +2,39 @@
 
 The Open Cryptography Kit for C to which this document refers is based on the C language and is usable by products that are based on C or C++.
 
-# Build for Linux 64
+## Build instructions
 
+For a debug build on any platform specify CONFIG=debug as an argument to make.
+
+### Linux 64-bit
+
+```bash
 make -k -C icc OPSYS=AMD64_LINUX create_all
 make -k -C icc OPSYS=AMD64_LINUX all
+```
 
-Other options include CONFIG=debug
-
-# Build for Linux 32 bit
+### Linux 32-bit
 
+```bash
 make -k -C icc OPSYS=LINUX create_all
 make -k -C icc OPSYS=LINUX all
+```
 
-Other options as above
-
-# Build for Windows 64
+### Windows 64-bit
 
+```bash
 make -k -C icc OPSYS=WIN64_VS2022 create_all
 make -k -C icc OPSYS=WIN64_VS2022 all
-
-Other options as above
-
-Note this build is not constrained to MS VS 2022 but is tested on that platform
+```
+This build is not constrained to MS VS 2022 but is tested on that platform.  
+#### Requirements
+Visual studio build tools are required, including mfc.  
+The supported make is windows gnumake 3.81. Also required is NASM, common unix utilities for windows (ls, sh, mv, rm, patch, etc), strawberry perl, and openjdk.  
+  
+Tested unix utilities are provided by msys2, or those packaged with the windows git installer.  
+The tested openjdk is the Microsoft Build of OpenJDK 17.  
+NASM should be added to the windows PATH environment variable.  
+Run the appropriate vcvars.bat file in a cmd.exe or otherwise use a development console before running make.  
+  
+Note: Windows utilities which use a Unix style PATH such as the gnumake available in msys2 are not supported.  
+Note: Cygwin is not supported.