Fix the Appveyor build for `gnu` targets all the way up to upstream

tests.

For some reason, the tests are hitting linking errors for me locally,
but in Appveyor they run just fine.

.appveyor.yml

@@ -6,7 +6,11 @@ environment:
 
   matrix:
     - TARGET: x86_64-pc-windows-gnu
+      MSYSTEM: MINGW64
+      CPU: x86_64
     - TARGET: i686-pc-windows-gnu
+      MSYSTEM: MINGW32
+      CPU: i686
 
 matrix:
   allow_failures:
@@ -14,17 +18,14 @@ matrix:
     - TARGET: i686-pc-windows-gnu
 
 install:
-  - ps: >-
-      If ($Env:TARGET -eq 'x86_64-pc-windows-gnu') {
-        $Env:PATH += ';C:\msys64\mingw64\bin'
-      } ElseIf ($Env:TARGET -eq 'i686-pc-windows-gnu') {
-        $Env:PATH += ';C:\msys64\mingw32\bin'
-      }
+  - set PATH=c:\msys64\%MSYSTEM%\bin;c:\msys64\usr\bin;%PATH%
+  - pacman --noconfirm -Syu mingw-w64-%CPU%-make
   - appveyor-retry appveyor DownloadFile https://win.rustup.rs/ -FileName rustup-init.exe
   - rustup-init.exe -y --default-host %TARGET% --default-toolchain nightly
   - set PATH=%PATH%;C:\Users\appveyor\.cargo\bin
   - rustc -vV
   - cargo -vV
+  - git submodule update --init --recursive
 
 build: false
 

jemalloc-sys/build.rs

@@ -306,6 +306,7 @@ fn main() {
     let make = make_cmd(&host);
     run(Command::new(make)
         .current_dir(&build_dir)
+        .arg("srcroot=../jemalloc/")
         .arg("-j")
         .arg(num_jobs.clone()));
 
@@ -314,17 +315,22 @@ fn main() {
         // Make tests:
         run(Command::new(make)
             .current_dir(&build_dir)
+            .arg("srcroot=../jemalloc/")
             .arg("-j")
             .arg(num_jobs.clone())
             .arg("tests"));
 
         // Run tests:
-        run(Command::new(make).current_dir(&build_dir).arg("check"));
+        run(Command::new(make)
+            .current_dir(&build_dir)
+            .arg("srcroot=../jemalloc/")
+            .arg("check"));
     }
 
     // Make install:
     run(Command::new(make)
         .current_dir(&build_dir)
+        .arg("srcroot=../jemalloc/")
         .arg("install_lib_static")
         .arg("install_include")
         .arg("-j")
@@ -382,6 +388,8 @@ fn make_cmd(host: &str) -> &'static str {
     const GMAKE_HOSTS: &[&str] = &["bitrig", "dragonfly", "freebsd", "netbsd", "openbsd"];
     if GMAKE_HOSTS.iter().any(|i| host.contains(i)) {
         "gmake"
+    } else if host.contains("windows") {
+        "mingw32-make"
     } else {
         "make"
     }