Refactor local `execvpe(3)` implementation

The previous code was prone to conflicts with when the platform happens
to expose a `execvpe(3)` implementation in its libc.

This commit renames the internal implementation to `__hsunix_execvpe` as
well as adding an autoconf-detection for the presence of `execvpe(3)`,
in which case `__hsunix_execvpe()` forwards the call to `execvpe(3)`.

Moreover, the code has been cleaned up to remove likely bitrotted CPP
conditionals.

This should fix #22

(This also partially addresses #11 on platforms which have a
libc-provided `execvpe(3)`)

1 files changed, 14 insertions, 0 deletions

diff --git a/cbits/ghcrts.c b/cbits/ghcrts.c
new file mode 100644
index 0000000..1e0dc1c
--- /dev/null
+++ b/cbits/ghcrts.c
@@ -0,0 +1,14 @@
+#include "execvpe.h"
+
+#ifdef __GLASGOW_HASKELL__
+// for 'void StopTimer(void)' prototype
+# include "Rts.h"
+#endif
+
+/* Copied verbatim from ghc/lib/std/cbits/system.c. */
+void pPrPr_disableITimers (void)
+{
+#ifdef __GLASGOW_HASKELL__
+    stopTimer();
+#endif
+}