Bump toolchain versions

• gcc 9.2.0 -> 9.3.0
• binutils 2.32 -> 2.34.5491
• crt-git 7.0.0 -> 8.0.0.5685

ghc-toolchain.py

@@ -26,22 +26,27 @@ def package(name: str, archs: List[Arch] = ARCHS) -> Dict[Arch, Url]:
     }
     return { arch: URLS[arch] for arch in archs }
 
+# Version numbers
+crt_ver = '8.0.0.5685.ef310786'
+winpthreads_ver = '8.0.0.5680.0df6b89f'
+gcc_ver = '9.3.0'
+
 # type: List[Dict[Arch, Url]]
 packages = [
-    package('crt-git-7.0.0.5491.fe45801e-1'),
-    package('headers-git-7.0.0.5490.9ec54ed1-1'),
-    package('winpthreads-git-7.0.0.5480.e14d23be-1'),
-    package('libwinpthread-git-7.0.0.5480.e14d23be-1', archs=['i686', 'x86_64']),
+    package(f'crt-git-{crt_ver}-1'),
+    package(f'headers-git-{crt_ver}-1'),
+    package(f'winpthreads-git-{winpthreads_ver}-1'),
+    package(f'libwinpthread-git-{winpthreads_ver}-1', archs=['i686', 'x86_64']),
     package('zlib-1.2.8-9'),
-    package('isl-0.21-1'),
+    package('isl-0.22.1-1'),
     package('mpfr-4.0.2-2'),
-    package('gmp-6.1.2-1'),
-    package('binutils-2.32-3'),
-    package('libidn2-2.2.0-1'),
-    package('gcc-9.2.0-1'),
+    package('gmp-6.2.0-1'),
+    package('binutils-2.34-1'),
+    package('libidn2-2.3.0-1'),
+    package(f'gcc-{gcc_ver}-1'),
     package('mpc-1.1.0-1'),
     package('windows-default-manifest-6.4-3'),
-    package('gcc-libs-9.2.0-1', archs=['i686', 'x86_64']),
+    package(f'gcc-libs-{gcc_ver}-1', archs=['i686', 'x86_64']),
 ]
 
 def download(url: str, dest: Path):