We seem to historically prefer pthreads instead of native threads.

https://github.com/lurcher/unixODBC/commit/7d72255824cb96599e71d19fbbc94405db658274#r108478182

Historically we were suggesting -lsocket -lnsl -lgen -z ignore for our users.

--- unixODBC-2.3.11/DriverManager/odbc.pc.in
+++ unixODBC-2.3.11/DriverManager/odbc.pc.in
@@ -17,4 +17,4 @@ URL: http://unixodbc.org
 Version: @PACKAGE_VERSION@
 Cflags: -I${includedir}
 Libs: -L${libdir} -lodbc
-Libs.private: @LIBLTDL@ @LIBS@
+Libs.private: @LIBLTDL@ @LIBS@ -lsocket -lnsl -lgen -z ignore
--- unixODBC-2.3.11/configure.ac
+++ unixODBC-2.3.11/configure.ac
@@ -394,9 +394,9 @@ AC_DEFINE([HAVE_LIBPTH], [1], [Use the -
   else
     gotthread="no";
 
-	AC_MSG_CHECKING( if os is AIX )
+	AC_MSG_CHECKING( if $host_os os is AIX or Solaris )
 	case $host_os in
-    	"aix"*)
+    	"aix"|"solaris"*)
 			raw_threads="no";
 			AC_MSG_RESULT( yes - disable check for libthread );
     	;;
--- unixODBC-2.3.11/odbcinst/odbcinst.pc.in
+++ unixODBC-2.3.11/odbcinst/odbcinst.pc.in
@@ -9,4 +9,4 @@ URL: http://unixodbc.org
 Version: @PACKAGE_VERSION@
 Cflags: -I${includedir}
 Libs: -L${libdir} -lodbcinst
-Libs.private: @LIBLTDL@ @LIBS@
+Libs.private: @LIBLTDL@ @LIBS@ -lsocket -lnsl -lgen -z ignore