From f582705de065e83323e482eee62e9bacc11cae16 Mon Sep 17 00:00:00 2001
From: Sergey Markelov <sergey@solidstatenetworks.com>
Date: Sat, 28 Mar 2026 10:20:11 +0700
Subject: [PATCH] cmake: improve: configure proxyres_config.h for preprocessor
 conditions

---
 CMakeLists.txt       | 20 +++++++++++---------
 fetch_posix.c        |  7 ++++++-
 net_adapter_linux.c  |  7 ++++++-
 net_adapter_mac.c    |  2 ++
 net_util.c           |  7 ++++++-
 proxyres_config.h.in |  5 +++++
 wpad_dhcp_posix.c    |  7 ++++++-
 wpad_dns.c           |  7 ++++++-
 8 files changed, 48 insertions(+), 14 deletions(-)
 create mode 100644 proxyres_config.h.in

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 246c3865..cbb9b8ab 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -40,7 +40,8 @@ set(PROXYRES_HDRS
     include/proxyres/config.h
     include/proxyres/log.h
     include/proxyres/proxyres.h
-    include/proxyres/resolver.h)
+    include/proxyres/resolver.h
+    ${PROJECT_BINARY_DIR}/proxyres_config.h)
 if(PROXYRES_EXECUTE)
     list(APPEND PROXYRES_HDRS
         include/proxyres/execute.h)
@@ -254,6 +255,13 @@ if(PROXYRES_USE_CXX)
     endif()
 endif()
 
+if(NOT WIN32)
+    check_include_file("net/if_arp.h" HAVE_NET_IF_ARP_H)
+    check_include_file("netdb.h" HAVE_NETDB_H)
+endif()
+
+configure_file(proxyres_config.h.in proxyres_config.h @ONLY NEWLINE_STYLE UNIX)
+
 add_library(proxyres ${PROXYRES_HDRS} ${PROXYRES_SRCS} ${PROXYRES_C_SRCS})
 set_property(TARGET proxyres PROPERTY C_STANDARD 11 CXX_STANDARD 11)
 if(PROXYRES_BUILD_TESTS)
@@ -261,17 +269,11 @@ if(PROXYRES_BUILD_TESTS)
 endif()
 target_include_directories(proxyres PRIVATE
     ${CMAKE_CURRENT_SOURCE_DIR}
-    ${CMAKE_CURRENT_SOURCE_DIR}/include/proxyres)
+    ${CMAKE_CURRENT_SOURCE_DIR}/include/proxyres
+    ${PROJECT_BINARY_DIR})
 target_include_directories(proxyres PUBLIC
     $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>)
 
-if(NOT WIN32)
-    check_include_file("net/if_arp.h" HAVE_NET_IF_ARP_H)
-    if(HAVE_NET_IF_ARP_H)
-        target_compile_definitions(proxyres PRIVATE HAVE_NET_IF_ARP_H)
-    endif()
-endif()
-
 if(PROXYRES_CURL AND (PROXYRES_EXECUTE OR PROXYRES_BUILD_CLI))
     if(NOT TARGET CURL::libcurl)
         include(FetchContent)
diff --git a/fetch_posix.c b/fetch_posix.c
index bf4f0a91..95584ba4 100644
--- a/fetch_posix.c
+++ b/fetch_posix.c
@@ -1,3 +1,5 @@
+#include "proxyres_config.h"
+
 #include <stdint.h>
 #include <stdbool.h>
 #include <stdlib.h>
@@ -6,13 +8,16 @@
 #include <string.h>
 #include <errno.h>
 
+#if HAVE_NETDB_H
+#  include <netdb.h>
+#endif
+
 #ifdef _WIN32
 #  include <winsock2.h>
 #  include <ws2tcpip.h>
 #else
 #  include <sys/types.h>
 #  include <sys/socket.h>
-#  include <netdb.h>
 #  include <unistd.h>
 #endif
 
diff --git a/net_adapter_linux.c b/net_adapter_linux.c
index 3725ff1a..3cfa2d1e 100644
--- a/net_adapter_linux.c
+++ b/net_adapter_linux.c
@@ -1,12 +1,17 @@
+#include "proxyres_config.h"
+
 #include <stdint.h>
 #include <stdbool.h>
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
 
+#if HAVE_NETDB_H
+#  include <netdb.h>
+#endif
+
 #include <sys/types.h>
 #include <sys/socket.h>
-#include <netdb.h>
 #include <unistd.h>
 #include <ifaddrs.h>
 #include <net/if.h>
diff --git a/net_adapter_mac.c b/net_adapter_mac.c
index b49d3f6b..ec46e033 100644
--- a/net_adapter_mac.c
+++ b/net_adapter_mac.c
@@ -1,3 +1,5 @@
+#include "proxyres_config.h"
+
 #include <stdint.h>
 #include <stdbool.h>
 #include <stdlib.h>
diff --git a/net_util.c b/net_util.c
index 43fcb229..833e986c 100644
--- a/net_util.c
+++ b/net_util.c
@@ -1,3 +1,5 @@
+#include "proxyres_config.h"
+
 #include <stdint.h>
 #include <stdbool.h>
 #include <stddef.h>
@@ -6,6 +8,10 @@
 #include <string.h>
 #include <errno.h>
 
+#if HAVE_NETDB_H
+#  include <netdb.h>
+#endif
+
 #ifdef _WIN32
 #  include <winsock2.h>
 #  include <ws2tcpip.h>
@@ -13,7 +19,6 @@
 #  include <arpa/inet.h>
 #  include <sys/types.h>
 #  include <sys/socket.h>
-#  include <netdb.h>
 #  include <unistd.h>
 #endif
 
diff --git a/proxyres_config.h.in b/proxyres_config.h.in
new file mode 100644
index 00000000..2158a115
--- /dev/null
+++ b/proxyres_config.h.in
@@ -0,0 +1,5 @@
+// Define to 1 if you have the <net/if_arp.h> header file.
+#cmakedefine HAVE_NET_IF_ARP_H 1
+
+// Define to 1 if you have the <netdb.h> header file.
+#cmakedefine HAVE_NETDB_H 1
diff --git a/wpad_dhcp_posix.c b/wpad_dhcp_posix.c
index cf0c4308..407e0360 100644
--- a/wpad_dhcp_posix.c
+++ b/wpad_dhcp_posix.c
@@ -1,3 +1,5 @@
+#include "proxyres_config.h"
+
 #include <stdint.h>
 #include <stdbool.h>
 #include <stdlib.h>
@@ -7,6 +9,10 @@
 #include <time.h>
 #include <errno.h>
 
+#if HAVE_NETDB_H
+#  include <netdb.h>
+#endif
+
 #ifdef _WIN32
 #  include <winsock2.h>
 #  include <ws2tcpip.h>
@@ -15,7 +21,6 @@
 #  include <arpa/inet.h>
 #  include <sys/types.h>
 #  include <sys/socket.h>
-#  include <netdb.h>
 #  include <unistd.h>
 #endif
 
diff --git a/wpad_dns.c b/wpad_dns.c
index 09d650a7..8c783d9c 100644
--- a/wpad_dns.c
+++ b/wpad_dns.c
@@ -1,3 +1,5 @@
+#include "proxyres_config.h"
+
 #include <stdint.h>
 #include <stdbool.h>
 #include <stdio.h>
@@ -6,6 +8,10 @@
 #include <string.h>
 #include <errno.h>
 
+#if HAVE_NETDB_H
+#  include <netdb.h>
+#endif
+
 #ifdef _WIN32
 #  include <winsock2.h>
 #  include <ws2tcpip.h>
@@ -13,7 +19,6 @@
 #else
 #  include <sys/types.h>
 #  include <sys/socket.h>
-#  include <netdb.h>
 #  include <unistd.h>
 #endif