diff --git a/opal/mca/hwloc/hwloc.h b/opal/mca/hwloc/hwloc.h
index 50a2ee65a1..48574b926f 100644
--- a/opal/mca/hwloc/hwloc.h
+++ b/opal/mca/hwloc/hwloc.h
@@ -63,7 +63,6 @@ typedef struct opal_hwloc_base_component_2_0_0_t opal_hwloc_component_t;
     MCA_BASE_VERSION_2_0_0, \
     "hwloc", 2, 0, 0
 
-END_C_DECLS
 
 /* Define a hierarchical level value that
  * helps resolve the hwloc behavior of
@@ -216,4 +215,6 @@ OPAL_DECLSPEC extern bool opal_hwloc_use_hwthreads_as_cpus;
 
 #endif
 
+END_C_DECLS
+
 #endif /* OPAL_HWLOC_H_ */
diff --git a/opal/mca/hwloc/hwloc142/hwloc/src/bind.c b/opal/mca/hwloc/hwloc142/hwloc/src/bind.c
index 26fc4f9ffb..4297aa4fbe 100644
--- a/opal/mca/hwloc/hwloc142/hwloc/src/bind.c
+++ b/opal/mca/hwloc/hwloc142/hwloc/src/bind.c
@@ -17,7 +17,9 @@
 #  include <malloc.h>
 #endif
 
+#ifdef HAVE_UNISTD_H
 #include <unistd.h>
+#endif
 #include <stdlib.h>
 #include <errno.h>
 
diff --git a/opal/mca/hwloc/hwloc142/hwloc/src/dolib.c b/opal/mca/hwloc/hwloc142/hwloc/src/dolib.c
index 7087a74ec5..016b4bb6bc 100644
--- a/opal/mca/hwloc/hwloc142/hwloc/src/dolib.c
+++ b/opal/mca/hwloc/hwloc142/hwloc/src/dolib.c
@@ -7,7 +7,9 @@
 
 /* Wrapper to avoid msys' tendency to turn / into \ and : into ;  */
 
+#ifdef HAVE_UNISTD_H
 #include <unistd.h>
+#endif
 #include <stdio.h>
 #include <stdlib.h>
 
@@ -31,11 +33,20 @@ int main(int argc, char *argv[]) {
   if (sscanf(version, "%d:%d:%d", &current, &revision, &age) != 3)
     exit(EXIT_FAILURE);
 
+#ifndef _WIN32
   snprintf(name, sizeof(name), "libhwloc-%d", current - age);
+#else
+  _snprintf(name, sizeof(name), "libhwloc-%d", current - age);
+#endif
   printf("using soname %s\n", name);
-
+  
+#ifndef _WIN32
   snprintf(s, sizeof(s), "\"%s\" /machine:%s /def:%s /name:%s /out:%s",
       prog, arch, def, name, lib);
+#else
+  _snprintf(s, sizeof(s), "\"%s\" /machine:%s /def:%s /name:%s /out:%s",
+      prog, arch, def, name, lib);
+#endif
   if (system(s)) {
     fprintf(stderr, "%s failed\n", s);
     exit(EXIT_FAILURE);
diff --git a/opal/mca/hwloc/hwloc142/hwloc/src/topology-synthetic.c b/opal/mca/hwloc/hwloc142/hwloc/src/topology-synthetic.c
index 41aa9880fb..7f3f8adf67 100644
--- a/opal/mca/hwloc/hwloc142/hwloc/src/topology-synthetic.c
+++ b/opal/mca/hwloc/hwloc142/hwloc/src/topology-synthetic.c
@@ -14,7 +14,9 @@
 
 #include <limits.h>
 #include <assert.h>
+#ifndef _WIN32
 #include <strings.h>
+#endif
 
 /* Read from DESCRIPTION a series of integers describing a symmetrical
    topology and update `topology->synthetic_description' accordingly.  On
diff --git a/opal/mca/hwloc/hwloc142/hwloc/src/topology-windows.c b/opal/mca/hwloc/hwloc142/hwloc/src/topology-windows.c
index 9bca5b7baf..14d47c0dda 100644
--- a/opal/mca/hwloc/hwloc142/hwloc/src/topology-windows.c
+++ b/opal/mca/hwloc/hwloc142/hwloc/src/topology-windows.c
@@ -307,9 +307,9 @@ hwloc_win_get_thisproc_membind(hwloc_topology_t topology, hwloc_nodeset_t nodese
   return hwloc_win_get_proc_membind(topology, GetCurrentProcess(), nodeset, policy, flags);
 }
 
-static LPVOID WINAPI (*VirtualAllocExNumaProc)(HANDLE hProcess, LPVOID lpAddress, SIZE_T dwSize, DWORD flAllocationType, DWORD flProtect, DWORD nndPreferred);
-static BOOL WINAPI (*VirtualFreeExProc)(HANDLE hProcess, LPVOID lpAddress, SIZE_T dwSize, DWORD dwFreeType);
-static BOOL WINAPI (*QueryWorkingSetExProc)(HANDLE hProcess, PVOID pv, DWORD cb);
+static LPVOID (WINAPI *VirtualAllocExNumaProc)(HANDLE hProcess, LPVOID lpAddress, SIZE_T dwSize, DWORD flAllocationType, DWORD flProtect, DWORD nndPreferred);
+static BOOL (WINAPI *VirtualFreeExProc)(HANDLE hProcess, LPVOID lpAddress, SIZE_T dwSize, DWORD dwFreeType);
+static BOOL (WINAPI *QueryWorkingSetExProc)(HANDLE hProcess, PVOID pv, DWORD cb);
 
 static int hwloc_win_get_VirtualAllocExNumaProc(void) {
   if (VirtualAllocExNumaProc == NULL) {
@@ -463,10 +463,10 @@ hwloc_win_get_area_membind(hwloc_topology_t topology __hwloc_attribute_unused, c
 void
 hwloc_look_windows(struct hwloc_topology *topology)
 {
-  BOOL WINAPI (*GetLogicalProcessorInformationProc)(PSYSTEM_LOGICAL_PROCESSOR_INFORMATION Buffer, PDWORD ReturnLength);
-  BOOL WINAPI (*GetLogicalProcessorInformationExProc)(LOGICAL_PROCESSOR_RELATIONSHIP relationship, PSYSTEM_LOGICAL_PROCESSOR_INFORMATION_EX Buffer, PDWORD ReturnLength);
-  BOOL WINAPI (*GetNumaAvailableMemoryNodeProc)(UCHAR Node, PULONGLONG AvailableBytes);
-  BOOL WINAPI (*GetNumaAvailableMemoryNodeExProc)(USHORT Node, PULONGLONG AvailableBytes);
+  BOOL (WINAPI *GetLogicalProcessorInformationProc)(PSYSTEM_LOGICAL_PROCESSOR_INFORMATION Buffer, PDWORD ReturnLength);
+  BOOL (WINAPI *GetLogicalProcessorInformationExProc)(LOGICAL_PROCESSOR_RELATIONSHIP relationship, PSYSTEM_LOGICAL_PROCESSOR_INFORMATION_EX Buffer, PDWORD ReturnLength);
+  BOOL (WINAPI *GetNumaAvailableMemoryNodeProc)(UCHAR Node, PULONGLONG AvailableBytes);
+  BOOL (WINAPI *GetNumaAvailableMemoryNodeExProc)(USHORT Node, PULONGLONG AvailableBytes);
   SYSTEM_INFO SystemInfo;
 
   DWORD length;
diff --git a/opal/mca/hwloc/hwloc142/hwloc/src/topology-xml.c b/opal/mca/hwloc/hwloc142/hwloc/src/topology-xml.c
index e595fa1f8b..ceb764e211 100644
--- a/opal/mca/hwloc/hwloc142/hwloc/src/topology-xml.c
+++ b/opal/mca/hwloc/hwloc142/hwloc/src/topology-xml.c
@@ -13,7 +13,9 @@
 #include <private/debug.h>
 
 #include <assert.h>
+#ifndef _WIN32
 #include <strings.h>
+#endif
 
 #ifdef HWLOC_HAVE_LIBXML2
 #include <libxml/parser.h>
diff --git a/opal/mca/hwloc/hwloc142/hwloc/src/topology.c b/opal/mca/hwloc/hwloc142/hwloc/src/topology.c
index 416abd22f0..880e2fb374 100644
--- a/opal/mca/hwloc/hwloc142/hwloc/src/topology.c
+++ b/opal/mca/hwloc/hwloc142/hwloc/src/topology.c
@@ -11,8 +11,12 @@
 #define _ATFILE_SOURCE
 #include <assert.h>
 #include <sys/types.h>
+#ifndef WIN32
 #include <dirent.h>
+#endif
+#ifdef HAVE_UNISTD_H
 #include <unistd.h>
+#endif
 #include <string.h>
 #include <errno.h>
 #include <stdio.h>