Allow disabling random_r() usage manually. See #279.

This allows building hmatrix against the musl libc,
which allows easily linking Haskell programs statically.

A feature-detection for random_r() would be even better,
but this will do for now.

2 files changed, 12 insertions, 4 deletions

diff --git a/packages/base/hmatrix.cabal b/packages/base/hmatrix.cabal
index 1380a36..c371ae7 100644
--- a/packages/base/hmatrix.cabal
+++ b/packages/base/hmatrix.cabal
@@ -36,6 +36,11 @@ flag disable-default-paths
     default:        False
     manual: True
 
+flag no-random_r
+    description:    When enabled, don't depend on the random_r() C function.
+    default:        False
+    manual: True
+
 library
 
     Build-Depends:      base >= 4.8 && < 5,
@@ -99,6 +104,9 @@ library
         cc-options:     -msse2
 
 
+    if flag(no-random_r)
+        cc-options: -DNO_RANDOM_R
+
     if os(OSX)
         if flag(openblas)
             if !flag(disable-default-paths)
diff --git a/packages/base/src/Internal/C/vector-aux.c b/packages/base/src/Internal/C/vector-aux.c
index dcd6c0b..08dc835 100644
--- a/packages/base/src/Internal/C/vector-aux.c
+++ b/packages/base/src/Internal/C/vector-aux.c
@@ -932,20 +932,20 @@ int vectorScan(char * file, int* n, double**pp){
 
 ////////////////////////////////////////////////////////////////////////////////
 
-#if defined (__APPLE__) || (__FreeBSD__)
+#if defined (__APPLE__) || (__FreeBSD__) || defined(NO_RANDOM_R)
 /* FreeBSD and Mac OS X do not provide random_r(), thread safety cannot be
    guaranteed.
    For FreeBSD and Mac OS X, nrand48() is much better than random().
    See: http://www.evanjones.ca/random-thread-safe.html
 */
-#pragma message "randomVector is not thread-safe in OSX and FreeBSD"
+#pragma message "randomVector is not thread-safe in OSX and FreeBSD or with NO_RANDOM_R"
 #endif
 
-#if defined (__APPLE__) || (__FreeBSD__) || defined(_WIN32) || defined(WIN32)
+#if defined (__APPLE__) || (__FreeBSD__) || defined(NO_RANDOM_R) || defined(_WIN32) || defined(WIN32)
 /* Windows use thread-safe random
    See: http://stackoverflow.com/questions/143108/is-windows-rand-s-thread-safe
 */
-#if defined (__APPLE__) || (__FreeBSD__)
+#if defined (__APPLE__) || (__FreeBSD__) || defined(NO_RANDOM_R)
 
 inline double urandom() {
     /* the probalility of matching will be theoretically p^3(in fact, it is not)