diff --git a/src/openssl/lib_crypto.cr b/src/openssl/lib_crypto.cr
index 8d450b28ff17..55551baab988 100644
--- a/src/openssl/lib_crypto.cr
+++ b/src/openssl/lib_crypto.cr
@@ -1,6 +1,6 @@
 {% begin %}
   lib LibCrypto
-    {% if flag?(:win32) %}
+    {% if flag?(:msvc) %}
       {% from_libressl = false %}
       {% ssl_version = nil %}
       {% for dir in Crystal::LIBRARY_PATH.split(Crystal::System::Process::HOST_PATH_DELIMITER) %}
@@ -13,10 +13,10 @@
       {% end %}
       {% ssl_version ||= "0.0.0" %}
     {% else %}
-      {% from_libressl = (`hash pkg-config 2> /dev/null || printf %s false` != "false") &&
-                         (`test -f $(pkg-config --silence-errors --variable=includedir libcrypto)/openssl/opensslv.h || printf %s false` != "false") &&
-                         (`printf "#include <openssl/opensslv.h>\nLIBRESSL_VERSION_NUMBER" | ${CC:-cc} $(pkg-config --cflags --silence-errors libcrypto || true) -E -`.chomp.split('\n').last != "LIBRESSL_VERSION_NUMBER") %}
-      {% ssl_version = `hash pkg-config 2> /dev/null && pkg-config --silence-errors --modversion libcrypto || printf %s 0.0.0`.split.last.gsub(/[^0-9.]/, "") %}
+      {% from_libressl = (`sh -c 'hash pkg-config 2> /dev/null || printf %s false'` != "false") &&
+                         (`sh -c 'test -f $(pkg-config --silence-errors --variable=includedir libcrypto)/openssl/opensslv.h || printf %s false'` != "false") &&
+                         (`sh -c 'printf "#include <openssl/opensslv.h>\nLIBRESSL_VERSION_NUMBER" | ${CC:-cc} $(pkg-config --cflags --silence-errors libcrypto || true) -E -'`.chomp.split('\n').last != "LIBRESSL_VERSION_NUMBER") %}
+      {% ssl_version = `sh -c 'hash pkg-config 2> /dev/null && pkg-config --silence-errors --modversion libcrypto || printf %s 0.0.0'`.split.last.gsub(/[^0-9.]/, "") %}
     {% end %}
 
     {% if from_libressl %}
diff --git a/src/openssl/lib_ssl.cr b/src/openssl/lib_ssl.cr
index 6adb3f172a3b..cbf01e41217a 100644
--- a/src/openssl/lib_ssl.cr
+++ b/src/openssl/lib_ssl.cr
@@ -6,7 +6,7 @@ require "./lib_crypto"
 
 {% begin %}
   lib LibSSL
-    {% if flag?(:win32) %}
+    {% if flag?(:msvc) %}
       {% from_libressl = false %}
       {% ssl_version = nil %}
       {% for dir in Crystal::LIBRARY_PATH.split(Crystal::System::Process::HOST_PATH_DELIMITER) %}
@@ -19,10 +19,10 @@ require "./lib_crypto"
       {% end %}
       {% ssl_version ||= "0.0.0" %}
     {% else %}
-      {% from_libressl = (`hash pkg-config 2> /dev/null || printf %s false` != "false") &&
-                         (`test -f $(pkg-config --silence-errors --variable=includedir libssl)/openssl/opensslv.h || printf %s false` != "false") &&
-                         (`printf "#include <openssl/opensslv.h>\nLIBRESSL_VERSION_NUMBER" | ${CC:-cc} $(pkg-config --cflags --silence-errors libssl || true) -E -`.chomp.split('\n').last != "LIBRESSL_VERSION_NUMBER") %}
-      {% ssl_version = `hash pkg-config 2> /dev/null && pkg-config --silence-errors --modversion libssl || printf %s 0.0.0`.split.last.gsub(/[^0-9.]/, "") %}
+      {% from_libressl = (`sh -c 'hash pkg-config 2> /dev/null || printf %s false'` != "false") &&
+                         (`sh -c 'test -f $(pkg-config --silence-errors --variable=includedir libssl)/openssl/opensslv.h || printf %s false'` != "false") &&
+                         (`sh -c 'printf "#include <openssl/opensslv.h>\nLIBRESSL_VERSION_NUMBER" | ${CC:-cc} $(pkg-config --cflags --silence-errors libssl || true) -E -'`.chomp.split('\n').last != "LIBRESSL_VERSION_NUMBER") %}
+      {% ssl_version = `sh -c 'hash pkg-config 2> /dev/null && pkg-config --silence-errors --modversion libssl || printf %s 0.0.0'`.split.last.gsub(/[^0-9.]/, "") %}
     {% end %}
 
     {% if from_libressl %}