fix(mvfst) (#6159)

* fix(mvfst)

closes #6117

* -latomic

* force PATH

* test flags

* path tricks

projects/facebook.com/mvfst/package.yml

@@ -21,9 +21,13 @@ build:
     cmake.org: '*'
     linux:
       gnu.org/gcc: '*'
+      gnu.org/binutils: '*'
       gnu.org/make: '*'
       kernel.org/linux-headers: '*'
   script:
+    # llvm's `as` likes to be first, wrongly
+    - run: export PATH={{deps.gnu.org/binutils.prefix}}/bin:$PATH
+      if: linux
     - cmake -S . -B _build $CMAKE_ARGS
     - cmake --build _build
     - cmake --install _build
@@ -39,6 +43,9 @@ build:
       - -DBUILD_TESTS=OFF
       - -DCMAKE_POSITION_INDEPENDENT_CODE=ON
     linux:
+      CC: gcc
+      CXX: g++
+      LD: gcc
       CMAKE_ARGS:
         - -DCMAKE_CXX_FLAGS=-fPIC
         - -DCMAKE_EXE_LINKER_FLAGS=-Wl,-pie
@@ -52,8 +59,19 @@ test:
     curl.se: '*'
     linux:
       gnu.org/gcc: '*'
+      gnu.org/binutils: '*'
       gnu.org/make: '*'
+  env:
+    linux:
+      CC: gcc
+      CXX: g++
+      LD: gcc
+      CXXFLAGS: -Wl,-latomic,-lrt
   script:
+    # llvm's `as` likes to be first, wrongly
+    - run: export PATH={{deps.gnu.org/binutils.prefix}}/bin:$PATH
+      if: linux
+
     # The best test we know is to build the echo client/server sample from the source.
     - PADDED_VERSION=$(echo "{{version}}" | gawk -F. '{printf "%04d.%02d.%02d.%02d\n", $1, $2, $3, $4}')
     - curl -L "https://github.com/facebook/mvfst/archive/v$PADDED_VERSION.tar.gz" | tar -xz --strip-components=1