Fix release: set per-target CC/CXX for goreleaser-cross

Each OS/arch combination needs its specific cross-compiler:
darwin uses o64-clang/oa64-clang, linux uses gnu-gcc,
windows uses mingw32-gcc. Without these, the docker image
defaults to the linux compiler which fails on darwin targets.

Author: apgiorgi

.goreleaser.yaml

@@ -12,6 +12,34 @@ builds:
     binary: dci
     env:
       - CGO_ENABLED=1
+      - >-
+        {{- if eq .Os "darwin" }}
+          {{- if eq .Arch "amd64" }}CC=o64-clang
+          {{- else }}CC=oa64-clang
+          {{- end }}
+        {{- else if eq .Os "linux" }}
+          {{- if eq .Arch "amd64" }}CC=x86_64-linux-gnu-gcc
+          {{- else }}CC=aarch64-linux-gnu-gcc
+          {{- end }}
+        {{- else if eq .Os "windows" }}
+          {{- if eq .Arch "amd64" }}CC=x86_64-w64-mingw32-gcc
+          {{- else }}CC=/llvm-mingw/bin/aarch64-w64-mingw32-gcc
+          {{- end }}
+        {{- end }}
+      - >-
+        {{- if eq .Os "darwin" }}
+          {{- if eq .Arch "amd64" }}CXX=o64-clang++
+          {{- else }}CXX=oa64-clang++
+          {{- end }}
+        {{- else if eq .Os "linux" }}
+          {{- if eq .Arch "amd64" }}CXX=x86_64-linux-gnu-g++
+          {{- else }}CXX=aarch64-linux-gnu-g++
+          {{- end }}
+        {{- else if eq .Os "windows" }}
+          {{- if eq .Arch "amd64" }}CXX=x86_64-w64-mingw32-g++
+          {{- else }}CXX=/llvm-mingw/bin/aarch64-w64-mingw32-g++
+          {{- end }}
+        {{- end }}
     goos:
       - darwin
       - linux