Fix build without ASYNC_IO

Fix the following build failure without ASYNC_IO:

/home/buildroot/autobuild/run/instance-1/output-1/host/opt/ext-toolchain/bin/../lib/gcc/mipsel-buildroot-linux-uclibc/12.3.0/../../../../mipsel-buildroot-linux-uclibc/bin/ld: iozone_linux-noaio.o: in function `read_perf_test':
iozone.c:(.text+0x11a74): undefined reference to `end_async'

Fixes:
 - http://autobuild.buildroot.org/results/31a4f0ac9eeb71df5d2f40ffe9f1f256cb58e399

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Upstream: sent to capps@iozone.org

diff '--color=auto' -Nura iozone3_506.orig/src/current/iozone.c iozone3_506/src/current/iozone.c
--- iozone3_506.orig/src/current/iozone.c	2024-03-06 12:28:16.734023725 +0100
+++ iozone3_506/src/current/iozone.c	2024-03-06 12:39:14.453991162 +0100
@@ -9153,6 +9153,7 @@
 				}
 			  }
 			}
+#ifdef ASYNC_IO
 			if(async_flag)
 			{
 				if(no_copy_flag)
@@ -9160,6 +9161,7 @@
 				end_async(gc);
 				gc=0;
 			}
+#endif
 			buffer1=0;
 			if(hist_summary)
 			{
@@ -9634,6 +9636,7 @@
 				}
 			  }
 			}
+#ifdef ASYNC_IO
 			if(async_flag)
 			{
 				if(no_copy_flag)
@@ -9641,6 +9644,7 @@
 				end_async(gc);
 				gc=0;
 			}
+#endif
 			if(rlocking)
 			{
 				lock_offset=I_LSEEK(fd,0,SEEK_CUR);
@@ -10097,6 +10101,7 @@
 				}
 			   }
 			}
+#ifdef ASYNC_IO
 			if(async_flag)
 			{
 				if(no_copy_flag)
@@ -10104,6 +10109,7 @@
 				end_async(gc);
 				gc=0;
 			}
+#endif
 			if(rlocking)
 			{
 				mylockr((int) fd, (int) 0, (int)1,
@@ -10749,6 +10755,7 @@
 			   }
 			}
 		}
+#ifdef ASYNC_IO
 		if(async_flag)
 		{
 			if(no_copy_flag)
@@ -10756,6 +10763,7 @@
 			end_async(gc);
 			gc=0;
 		}
+#endif
 			
 		/* This is a bit tricky.  The goal is to read with a stride through
 		   the file. The problem is that you need to touch all of the file
@@ -15485,6 +15493,7 @@
 			   }
 		   }
 		}
+#ifdef ASYNC_IO
 		if(async_flag)
 		{
 			if(no_copy_flag)
@@ -15492,6 +15501,7 @@
 			end_async(gc);
 			gc=0;
 		}
+#endif
 		read_so_far+=reclen/1024;
 		r_traj_bytes_completed+=reclen;
 		r_traj_ops_completed++;
@@ -16050,6 +16060,7 @@
 			   }
 		   }
 		}
+#ifdef ASYNC_IO
 		if(async_flag)
 		{
 			if(no_copy_flag)
@@ -16057,6 +16068,7 @@
 			end_async(gc);
 			gc=0;
 		}
+#endif
 		read_so_far+=reclen/1024;
 		r_traj_bytes_completed+=reclen;
 		r_traj_ops_completed++;
@@ -16665,6 +16677,7 @@
 			}
 		   }
 		}
+#ifdef ASYNC_IO
 		if(async_flag)
 		{
 			if(no_copy_flag)
@@ -16672,6 +16685,7 @@
 			end_async(gc);
 			gc=0;
 		}
+#endif
 		re_read_so_far+=reclen/1024;
 		r_traj_bytes_completed+=reclen;
 		r_traj_ops_completed++;
@@ -17244,6 +17258,7 @@
 			  lock_offset, reclen);
 		}
 		current_position+=reclen;
+#ifdef ASYNC_IO
 		if(async_flag)
 		{
 			if(no_copy_flag)
@@ -17251,6 +17266,7 @@
 			end_async(gc);
 			gc=0;
 		}
+#endif
 		t_offset = (off64_t)reclen*2;
 		if (!(h_flag || k_flag || mmapflag))
 		{
@@ -17778,6 +17794,7 @@
 			}
 		   }
 		}
+#ifdef ASYNC_IO
 		if(async_flag)
 		{
 			if(no_copy_flag)
@@ -17785,6 +17802,7 @@
 			end_async(gc);
 			gc=0;
 		}
+#endif
 		if(current_position + (stride * reclen) >= (numrecs64 * reclen)-reclen) 
 		{
 			current_position=0;
@@ -18528,6 +18546,7 @@
 			}
 		   }
 		}
+#ifdef ASYNC_IO
 		if(async_flag)
 		{
 			if(no_copy_flag)
@@ -18535,6 +18554,7 @@
 			end_async(gc);
 			gc=0;
 		}
+#endif
 		ranread_so_far+=reclen/1024;
 		if(*stop_flag)
 		{