jamvm: Use <fenv.h> instead of <fpu_control.h>

musl libc (http://musl-libc.org lack the non-standard <fpu_control.h>
header, which is used in src/os/linux/{i386,x86_64}/init.c files to
setup the floating point precision. This patch makes it use the
standard C <fenv.h> header instead.

Original patch at Felix Janda at
https://sourceforge.net/p/jamvm/patches/6/

Signed-off-by: Guo Li <uxgood.org@gmail.com>

lang/jamvm/Makefile

@@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=jamvm
 PKG_VERSION:=2.0.0
-PKG_RELEASE:=1
+PKG_RELEASE:=2
 PKG_LICENSE:=GPL-2.0+
 PKG_MAINTAINER:=Dana H. Myers <k6jq@comcast.net>
 

lang/jamvm/patches/001-Use-fenv.h-instead-of-fpu_control.h.patch

@@ -0,0 +1,86 @@
+From 7152ded5219453c9ff1cd062cecbeaf4d77e4cab Mon Sep 17 00:00:00 2001
+From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
+Date: Thu, 26 May 2016 15:05:48 +0200
+Subject: [PATCH] Use <fenv.h> instead of <fpu_control.h>
+
+musl libc (http://musl-libc.org lack the non-standard <fpu_control.h>
+header, which is used in src/os/linux/{i386,x86_64}/init.c files to
+setup the floating point precision. This patch makes it use the
+standard C <fenv.h> header instead.
+
+Original patch at Felix Janda at
+https://sourceforge.net/p/jamvm/patches/6/.
+
+Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
+---
+ src/os/linux/i386/init.c   | 12 ++++++------
+ src/os/linux/x86_64/init.c | 16 ++++++----------
+ 2 files changed, 12 insertions(+), 16 deletions(-)
+
+diff --git a/src/os/linux/i386/init.c b/src/os/linux/i386/init.c
+index d9c6648..94a733e 100644
+--- a/src/os/linux/i386/init.c
++++ b/src/os/linux/i386/init.c
+@@ -19,18 +19,18 @@
+  * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+  */
+ 
+-#include <fpu_control.h>
++#include <fenv.h>
+ 
+ /* Change floating point precision to double (64-bit) from
+  * the extended (80-bit) Linux default. */
+ 
+ void setDoublePrecision() {
+-    fpu_control_t cw;
++    fenv_t fenv;
+ 
+-    _FPU_GETCW(cw);
+-    cw &= ~_FPU_EXTENDED;
+-    cw |= _FPU_DOUBLE;
+-    _FPU_SETCW(cw);
++    fegetenv(&fenv);
++    fenv.__control_word &= ~0x300; /* _FPU_EXTENDED */
++    fenv.__control_word |= 0x200; /* _FPU_DOUBLE */
++    fesetenv(&fenv);
+ }
+ 
+ void initialisePlatform() {
+diff --git a/src/os/linux/x86_64/init.c b/src/os/linux/x86_64/init.c
+index 9d55229..a76a923 100644
+--- a/src/os/linux/x86_64/init.c
++++ b/src/os/linux/x86_64/init.c
+@@ -19,9 +19,7 @@
+  * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+  */
+ 
+-#ifdef __linux__
+-#include <fpu_control.h>
+-#endif
++#include <fenv.h>
+ 
+ /* Change the x87 FPU precision to double (64-bit) from the extended
+    (80-bit) Linux default.  Note, unlike on i386, my testcases pass
+@@ -30,14 +28,12 @@
+ */
+ 
+ void setDoublePrecision() {
+-#ifdef __linux__
+-    fpu_control_t cw;
++    fenv_t fenv;
+ 
+-    _FPU_GETCW(cw);
+-    cw &= ~_FPU_EXTENDED;
+-    cw |= _FPU_DOUBLE;
+-    _FPU_SETCW(cw);
+-#endif
++    fegetenv(&fenv);
++    fenv.__control_word &= ~0x300; /*_FPU_EXTENDED */
++    fenv.__control_word |= 0x200; /*_FPU_DOUBLE */
++    fesetenv(&fenv);
+ }
+ 
+ void initialisePlatform() {
+-- 
+2.7.4
+