Forgot that conda build sets the compiler in a different place. Tryin…

…g this to set the

compiler version on Linux, while hopefully leaving it alone for other OSs.

This does work - a local test shows that gemmi now passes when the compiler versions
match.

recipes/sire/template.yaml

@@ -13,8 +13,6 @@ build:
 
 requirements:
   build:
-    - {{ compiler('c') }}
-    - {{ compiler('cxx') }}
     SIRE_BUILD_REQUIREMENTS
   host:
     SIRE_HOST_REQUIREMENTS

requirements_build.txt

@@ -1,5 +1,14 @@
 # Build requirements for Sire.
 
+# Need to specify the compiler as we have to control the version
+gcc==12.3.0 ; sys_platform == "linux"
+gxx==12.3.0 ; sys_platform == "linux"
+
+clang ; sys_platform == "darwin"
+clangxx ; sys_platform == "darwin"
+
+vc ; sys_platform == "win32"
+
 cmake
 git
 python