diff --git a/libzfcphbaapi-c99.patch b/libzfcphbaapi-c99.patch
new file mode 100644
index 0000000..f6afb12
--- /dev/null
+++ b/libzfcphbaapi-c99.patch
@@ -0,0 +1,46 @@
+Declare sysfs_getAdapterAttributes in vlib_sysfs.h, to avoid an
+implicit function declaration in vlib.c.
+
+Include <sys/time.h> in fc_tools/zfcp_ping.c for gettimeofday.
+
+Include <scsi/sg_cmds.h> in vlib_sg.c, to avoid further
+implicit function declarations.
+
+diff --git a/fc_tools/zfcp_ping.c b/fc_tools/zfcp_ping.c
+index 3cf90d8981936c20..0fa34c4702f4cfd2 100644
+--- a/fc_tools/zfcp_ping.c
++++ b/fc_tools/zfcp_ping.c
+@@ -13,6 +13,7 @@
+ #include <signal.h>
+ #include <hbaapi.h>
+ #include <errno.h>
++#include <sys/time.h>
+ #include "include/zfcp_util.h"
+ 
+ #define FC_PNG_REV              0x00000001
+diff --git a/vlib_sg.c b/vlib_sg.c
+index 78f0476378e23b2d..b60ffa6de6aea6db 100644
+--- a/vlib_sg.c
++++ b/vlib_sg.c
+@@ -21,6 +21,8 @@
+ 
+ #include "vlib.h"
+ 
++#include <scsi/sg_cmds.h>
++
+ #define INTERVAL	10000000
+ #define RETRIES		1500
+ 
+diff --git a/vlib_sysfs.h b/vlib_sysfs.h
+index 2da344e6d9f5f2ea..c8f9ead4f31c7c27 100644
+--- a/vlib_sysfs.h
++++ b/vlib_sysfs.h
+@@ -35,6 +35,8 @@ HBA_STATUS sysfs_createAndReadConfigPorts(struct vlib_adapter *);
+ HBA_STATUS sysfs_createAndReadConfigAdapter();
+ HBA_STATUS sysfs_getDiscoveredPortAttributes(HBA_PORTATTRIBUTES **,
+ 						struct vlib_port *);
++HBA_STATUS sysfs_getAdapterAttributes(HBA_ADAPTERATTRIBUTES **,
++						struct vlib_adapter *);
+ HBA_STATUS sysfs_getAdapterPortAttributes(HBA_PORTATTRIBUTES **,
+ 						struct vlib_adapter *);
+ HBA_STATUS sysfs_getPortStatistics(HBA_PORTSTATISTICS **,
diff --git a/libzfcphbaapi.spec b/libzfcphbaapi.spec
index 72add12..90ad7c1 100644
--- a/libzfcphbaapi.spec
+++ b/libzfcphbaapi.spec
@@ -3,12 +3,13 @@
 Name:           libzfcphbaapi
 Summary:        HBA API for the zFCP device driver
 Version:        2.2.0
-Release:        17%{?dist}
+Release:        18%{?dist}
 License:        CPL
 URL:            http://www.ibm.com/developerworks/linux/linux390/zfcp-hbaapi.html
 # http://www.ibm.com/developerworks/linux/linux390/zfcp-hbaapi-%%{hbaapiver}.html
 Source0:        http://download.boulder.ibm.com/ibmdl/pub/software/dw/linux390/ht_src/%{srcname}-%{version}.tar.gz
 Patch1:         %{srcname}-2.1.1-fedora.patch
+Patch2: libzfcphbaapi-c99.patch
 
 ExclusiveArch:  s390 s390x
 
@@ -44,6 +45,7 @@ Documentation in HTML format for the zFCP HBA API Library.
 %setup -q -n %{srcname}-%{version}
 
 %patch1 -p1 -b .fedora
+%patch2 -p1
 
 
 %build
@@ -91,6 +93,9 @@ fi
 
 
 %changelog
+* Fri Jan 27 2023 Florian Weimer <fweimer@redhat.com> - 2.2.0-18
+- Fix C99 compatibility issues (#2165019)
+
 * Thu Jan 19 2023 Fedora Release Engineering <releng@fedoraproject.org> - 2.2.0-17
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_38_Mass_Rebuild