stop ./configure at once on library failure

auto/lib/conf

diff --git a/auto/lib/conf b/auto/lib/conf
index 7da80e7..f52c904 100644
--- a/auto/lib/conf
+++ b/auto/lib/conf
@@ -4,8 +4,22 @@
 
 if [ $USE_PCRE = YES -o $PCRE != NONE ]; then
     . auto/lib/pcre/conf
+
+else
+    if [ $USE_PCRE = DISABLED -a $HTTP_REWRITE = YES ]; then
+
+cat << END
+
+$0: error: the HTTP rewrite module requires the PCRE library.
+You can either disable the module by using --without-http_rewrite_module
+option or you have to enable the PCRE support.
+
+END
+        exit 1
+    fi
 fi
 
+
 if [ $USE_OPENSSL = YES ]; then
     . auto/lib/openssl/conf
 fi

auto/lib/google-perftools/conf

diff --git a/auto/lib/google-perftools/conf b/auto/lib/google-perftools/conf
index a8987c9..67df9f8 100644
--- a/auto/lib/google-perftools/conf
+++ b/auto/lib/google-perftools/conf
@@ -30,4 +30,15 @@
 
 if [ $ngx_found = yes ]; then
     CORE_LIBS="$CORE_LIBS $ngx_feature_libs"
+
+else
+
+cat << END
+
+$0: error: the Google perftool module requires the Google perftools
+library. You can either do not enable the module or install the library.
+
+END
+
+    exit 1
 fi

auto/lib/md5/conf

diff --git a/auto/lib/md5/conf b/auto/lib/md5/conf
index 75dd130..d4ef007 100644
--- a/auto/lib/md5/conf
+++ b/auto/lib/md5/conf
@@ -94,6 +94,18 @@
             CORE_LIBS="$CORE_LIBS $ngx_feature_libs"
             MD5=YES
             MD5_LIB=$ngx_md5_lib
+        else
+
+cat << END
+
+$0: error: the HTTP cache module requires md5 functions
+from OpenSSL library.  You can either disable the module by using
+--without-http_cache option, or install the OpenSSL library into the system,
+or build the OpenSSL library statically from the source with nginx by using
+--with-openssl=<path> option.
+
+END
+            exit 1
         fi
 
     fi

auto/lib/openssl/conf

diff --git a/auto/lib/openssl/conf b/auto/lib/openssl/conf
index 8a762a2..731db80 100644
--- a/auto/lib/openssl/conf
+++ b/auto/lib/openssl/conf
@@ -66,6 +66,17 @@
                 have=NGX_SSL . auto/have
                 CORE_LIBS="$CORE_LIBS $ngx_feature_libs $NGX_LIBDL"
                 OPENSSL=YES
+            else
+
+cat << END
+
+$0: error: SSL modules require the OpenSSL library.
+You can either do not enable the modules, or install the OpenSSL library
+into the system, or build the OpenSSL library statically from the source
+with nginx by using --with-openssl=<path> option.
+
+END
+                exit 1
             fi
         ;;
 

auto/lib/pcre/conf

diff --git a/auto/lib/pcre/conf b/auto/lib/pcre/conf
index 3a26b85..71c6fc5 100644
--- a/auto/lib/pcre/conf
+++ b/auto/lib/pcre/conf
@@ -161,6 +161,18 @@
             CORE_INCS="$CORE_INCS $ngx_feature_path"
             CORE_LIBS="$CORE_LIBS $ngx_feature_libs"
             PCRE=YES
+        else
+
+cat << END
+
+$0: error: the HTTP rewrite module requires the PCRE library.
+You can either disable the module by using --without-http_rewrite_module
+option, or install the PCRE library into the system, or build the PCRE library
+statically from the source with nginx by using --with-pcre=<path> option.
+
+END
+            exit 1
+
         fi
 
     fi

auto/lib/zlib/conf

diff --git a/auto/lib/zlib/conf b/auto/lib/zlib/conf
index f033354..e44aa34 100644
--- a/auto/lib/zlib/conf
+++ b/auto/lib/zlib/conf
@@ -57,6 +57,17 @@
             CORE_LIBS="$CORE_LIBS $ngx_feature_libs"
             ZLIB=YES
             ngx_found=no
+        else
+
+cat << END
+
+$0: error: the HTTP gzip module requires the zlib library.
+You can either disable the module by using --without-http_gzip_module
+option, or install the zlib library into the system, or build the zlib library
+statically from the source with nginx by using --with-zlib=<path> option.
+
+END
+            exit 1
         fi
     fi