[gimp-macos-build] Add gfortran to the base

[Alex Samorukov <asamorukov src gnome org>]

commit 0d7216e4f94518b1060e259e7765f988929af6bf
Author: Oleksii Samorukov <oleksii_samorukov mckinsey com>
Date:   Fri Aug 30 15:07:52 2019 +0200

    Add gfortran to the base

 .circleci/config.yml | 8 ++++++++
 1 file changed, 8 insertions(+)
---
diff --git a/.circleci/config.yml b/.circleci/config.yml
index 58e2329..7c5be72 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -12,6 +12,14 @@ jobs:
         - run:
             name: Setup rust
             command: curl https://sh.rustup.rs -sSf | sh -s -- -y
+        - run:
+            name: Setup gfortran (openblas requirement)
+            command: |
+              cd ~/
+              curl -L 
'https://github.com/fxcoudert/gfortran-for-macOS/releases/download/8.2/gfortran-8.2-Mojave.dmg' > 
gfortran-8.2-Mojave.dmg
+              hdiutil mount gfortran-8.2-Mojave.dmg
+              sudo installer -pkg /Volumes/gfortran-8.2-Mojave/gfortran-8.2-Mojave/gfortran.pkg -target /
+              hdiutil unmount /Volumes/gfortran-8.2-Mojave
         - run:
             name: Setup 10.9 SDK
             command: |