docs: minor updates

Author: nfrechette

README.md

@@ -36,14 +36,14 @@ Unicode formats other than UTF-8 aren't supported.
 ## Supported platforms
 
 *  Windows VS2015 x86 and x64, VS2017/2019 x86, x64, and ARM64*
-*  Linux (gcc5, gcc6, gcc7, gcc8, clang4, clang5, clang6) x86 and x64
-*  OS X (Xcode 8.3, 9.4, 10.3) x86 and x64
+*  Linux (gcc5, gcc6, gcc7, gcc8, gcc9, clang4, clang5, clang6, clang7) x86 and x64
+*  OS X (Xcode 8.3, 9.4, 10.3, 11.2*) x86 and x64
 *  Android (NVIDIA CodeWorks with clang5) ARMv7-A and ARM64
 *  iOS (Xcode 8.3, 9.4, 10.3) ARM64
 
 The above supported platform list is only what is tested every release but if it compiles, it should run just fine.
 
-Note: *VS2017* and *VS2019* compile with *ARM64* on *AppVeyor* but I have no device to test them with.
+Notes: *VS2017* and *VS2019* compile with *ARM64* on *AppVeyor* but I have no device to test them with. Xcode 11 no longer supports x86.
 
 ## External dependencies