[flashrom] [PATCH] Add (implicit) support for musl libc.

[Stefan Tauner]

From: Gwenhael Goavec-Merou <gwenhael.goavec-merou at trabucayre.com>

This is mostly achieved by fixing or refining the inclusion of header
files and replacing glibc-specific ifdefs with more generic ones.

 - <sys/io.h>: Linux-specific and not only available in glibc. Include it
               if we are running Linux and not only if glibc is active.
 - <sys/fcntl.h>: should be (and is) replaced by <fcntl.h> (without the
    			  "sys" prefix).
 - <linux/spi/spidev.h>: Does not include all necessary headers, namely
                         _IOC_SIZEBITS that is used in the definition of
                         SPI_MSGSIZE is not brought in via <linux/ioctl.h>
                         but instead we relied so far on glibc's including
                         it via <sys/ioctl.h>. Change that to explicitly
                         including <linux/ioctl.h>.
 - <endian.h>: Would also be available in musl but there is no easy way
               to detect it so we do not try yet.

The bug report and initial patches were
Signed-off-by: Gwenhael Goavec-Merou <gwenhael.goavec-merou at trabucayre.com>

Signed-off-by: Stefan Tauner <stefan.tauner at alumni.tuwien.ac.at>
---

No regressions detected on the buildbot... flashrom can be built completely
(with libpci, libusb and libftdi programmers) with musl after applying this.

 hwaccess.h  | 3 ++-
 linux_spi.c | 5 +++--
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/hwaccess.h b/hwaccess.h
index 3e46192..25b1456 100644
--- a/hwaccess.h
+++ b/hwaccess.h
@@ -27,7 +27,7 @@
 #include "platform.h"
 
 #if IS_X86
-#if defined(__GLIBC__)
+#if defined(__linux__)
 #include <sys/io.h>
 #endif
 #endif
@@ -115,6 +115,7 @@
 #if !defined (__FLASHROM_BIG_ENDIAN__) && !defined (__FLASHROM_LITTLE_ENDIAN__)
 
 /* Nonstandard libc-specific macros for determining endianness. */
+/* musl provides an endian.h as well... but it can not be detected from within C. */
 #if defined(__GLIBC__)
 #include <endian.h>
 #if BYTE_ORDER == LITTLE_ENDIAN
diff --git a/linux_spi.c b/linux_spi.c
index 26725e1..19b4965 100644
--- a/linux_spi.c
+++ b/linux_spi.c
@@ -22,13 +22,14 @@
 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
-#include <sys/fcntl.h>
+#include <fcntl.h>
 #include <errno.h>
 #include <ctype.h>
 #include <unistd.h>
+#include <sys/ioctl.h>
 #include <linux/types.h>
 #include <linux/spi/spidev.h>
-#include <sys/ioctl.h>
+#include <linux/ioctl.h>
 #include "flash.h"
 #include "chipdrivers.h"
 #include "programmer.h"
-- 
Kind regards, Stefan Tauner