Use off_t instead of loff_t.  Both pread() and pwrite() take
off_t not loff_t types.  This breaks the build on musl.  See

https://bugs.gentoo.org/show_bug.cgi?id=541694

diff -Naur longrun.orig/longrun.c longrun/longrun.c
--- longrun.orig/longrun.c	2015-03-07 19:05:19.166652462 +0000
+++ longrun/longrun.c	2015-03-07 19:06:05.419651899 +0000
@@ -181,7 +181,7 @@
 }
 
 /* note: if an output is NULL, then don't set it */
-void read_msr(loff_t address, int *lower, int *upper)
+void read_msr(off_t address, int *lower, int *upper)
 {
 	uint32_t data[2];
 
@@ -193,7 +193,7 @@
 	if (upper) *upper = data[1];
 }
 
-void write_msr(loff_t address, int lower, int upper)
+void write_msr(off_t address, int lower, int upper)
 {
 	uint32_t data[2];
 
@@ -206,7 +206,7 @@
 }
 
 /* note: if an output is NULL, then don't set it */
-void read_cpuid(loff_t address, int *eax, int *ebx, int *ecx, int *edx)
+void read_cpuid(off_t address, int *eax, int *ebx, int *ecx, int *edx)
 {
 	uint32_t data[4];