mariadb: needs dynamic library support

In a static-only configuration, mariadb fails to build because it
tries to build a shared library:

[ 18%] Linking CXX shared module ha_spider.so
output/host/opt/ext-toolchain/bin/../lib/gcc/arm-buildroot-linux-uclibcgnueabi/6.4.0/../../../../arm-buildroot-linux-uclibcgnueabi/bin/ld: output/host/opt/ext-toolchain/bin/../lib/gcc/arm-buildroot-linux-uclibcgnueabi/6.4.0/../../../../arm-buildroot-linux-uclibcgnueabi/lib/libstdc++.a(eh_globals.o)(.text.__cxa_get_globals_fast+0x14): R_ARM_TLS_LE32 relocation not permitted in shared object

This is not detected by the autobuilders, because mariadb is part of a
Config.in choice, and such choices are not randomized by our current
testing infrastructure.

Signed-off-by: Ryan Coe <bluemrp9@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
(cherry picked from commit 58cb24d883b106e7795c0cdbda906a3c6cbc80ed)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/mysql/Config.in

@@ -17,6 +17,7 @@ choice
 config BR2_PACKAGE_MARIADB
 	bool "mariadb"
 	depends on BR2_PACKAGE_LIBAIO_ARCH_SUPPORTS
+	depends on !BR2_STATIC_LIBS
 	select BR2_PACKAGE_LIBAIO
 	select BR2_PACKAGE_LIBXML2
 	select BR2_PACKAGE_NCURSES
@@ -30,6 +31,10 @@ config BR2_PACKAGE_MARIADB
 
 	  http://www.mariadb.org/
 
+comment "mariadb needs a toolchain w/ dynamic library"
+	depends on BR2_PACKAGE_LIBAIO_ARCH_SUPPORTS
+	depends on BR2_STATIC_LIBS
+
 config BR2_PACKAGE_ORACLE_MYSQL
 	bool "oracle mysql"
 	select BR2_PACKAGE_NCURSES