prep-for-macos-build: only install brew when not found

Signed-off-by: Rob Browning <rlb@defaultvalue.org>

diff --git a/dev/prep-for-macos-build b/dev/prep-for-macos-build
index e8363d3ebcb30496b06c59f7935ec241bded3900..e64ab1d029347d12675bd673a5f625da1b554896 100755 (executable)
--- a/dev/prep-for-macos-build
+++ b/dev/prep-for-macos-build
@@ -9,7 +9,9 @@ usage()
 
 pyver="${1:-python2}"
 
-/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"
+if ! command -v brew; then
+    /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"
+fi
 
 brew update
 brew install par2 readline rsync pkg-config md5sha1sum